NOTICE: All slip opinions and orders are subject to formal revision and are superseded by the advance sheets and bound volumes of the Official Reports. If you find a typographical error or other formal error, please notify the Reporter of Decisions, Supreme Judicial Court, John Adams Courthouse, 1 Pemberton Square, Suite 2500, Boston, MA, 02108-1750; (617) 557-1030; [email protected]
SJC-12702
COMMONWEALTH vs. KEITH WILLIAMS.
Suffolk. December 8, 2025. - September 22, 2026.
Present: Budd, C.J., Gaziano, Wendlandt, Dewar,
& Wolohojian, JJ.
Homicide. Firearms. Armed Assault with Intent to Murder.
Assault and Battery by Means of a Dangerous Weapon.
Evidence, Firearm, Scientific test, Expert opinion,
Presumptions and burden of proof, Inference, Argument by
prosecutor, Identification. Witness, Expert.
Identification. Practice, Criminal, Presumptions and
burden of proof, Argument by prosecutor, New trial, Capital
case.
Indictments found and returned in the Superior Court Department on November 19, 2014.
The cases were tried before Christine M. Roach, J., and a motion for a new trial, filed on March 31, 2023, was heard by Katie Rayburn, J.
Robert F. Shaw, Jr., for the defendant.
Brooke Hartley, Assistant District Attorney (Mark T. Lee, Assistant District Attorney, also present) for the Commonwealth.
DEWAR, J. In 2017, a jury convicted the defendant, Keith
Williams, of murder in the first degree and three other offenses
2
in connection with the shooting and death of Dawn Jaffier and
the nonfatal shooting of Lealah Fulton amidst a parade in the
Dorchester section of Boston. Although no witness identified
the defendant as the shooter, he was seen nearby disposing of
the murder weapon seconds after the shooting, accompanied by two
other men whom witnesses did place at the scene of the shooting.
Before this court are the defendant's appeals from his
convictions and from an order denying his motion for a new
trial. Among other arguments, the defendant contends that the
trial judge erred in admitting certain expert testimony
regarding gunshot residue testing. The defendant and his two
companions were tested for gunshot residue in the hours after
the shooting, and all of the test results were negative. The
Commonwealth's expert testified that, in order to account for
the possibility of contamination and to ensure accurate
interpretation, a positive test result requires the detection of
at least three gunshot residue particles, and there is "nothing
to be drawn" from a negative result. The Commonwealth
nonetheless presented testimony from the expert that one gunshot
residue particle was found on the defendant's hand and another
on his T-shirt, whereas no particles were found on the other two
men, as evidence that the defendant was the shooter.
We agree with the defendant that the Commonwealth failed to
establish the reliability of using the subthreshold number of
3
gunshot residue particles detected in a negative test result as
evidence that the defendant was the shooter. To the contrary,
as stated, the Commonwealth's own expert testified that nothing
could be drawn from the negative test results. Accordingly, on
this record, the testimony about the subthreshold number of
gunshot residue particles should not have been admitted for that
purpose.
Because this error was prejudicial in the circumstances
here, the defendant is entitled to a new trial on his
convictions of murder in the first degree, armed assault with
intent to murder, and assault and battery by means of a
dangerous weapon. He may be tried again on the charge of murder
in the first degree, as we reject his further argument that
there was insufficient evidence presented at trial to prove that
he acted with deliberate premeditation. We also vacate without
need for further discussion the defendant's conviction of
carrying a firearm without a license, because the jury were not
instructed that the Commonwealth bore the burden of proving that
he did not have a valid firearm license. See Commonwealth v.
Carleton, 497 Mass. 11, 13 (2026), citing Commonwealth v.
Guardado, 493 Mass. 1, 12 (2023), cert. denied, 144 S. Ct. 2683
(2024). We thus set aside all of the defendant's convictions
and remand the case for further proceedings consistent with this
opinion.
4
Background. 1. Commonwealth's case. We recite the facts
the jury could have found, reserving some details for later
discussion. See Commonwealth v. Latimore, 378 Mass. 671, 677
(1979).
On the morning of August 23, 2014, a crowd gathered to
watch a parade on Blue Hill Avenue in Dorchester. As shown in
security camera footage, at approximately 7:26 A.M., the
defendant was with Jordan Reed and Brian Joyce outside a
convenience store on Blue Hill Avenue between Charlotte and
McLellan Streets.1 The defendant entered the store, made a
purchase, and left. About forty-five minutes later, Reed,
Joyce, and two other young men approached and entered the store
together. Shortly thereafter, Tevan Williams and Wesson Colas,
the codefendant, also entered.2 The interactions between the two
groups were tense, and, although no words were exchanged, they
"eyeball[ed]" each other.
Colas and Tevan left the store, followed less than one
minute later by Reed, Joyce, and the other two men accompanying
them. Colas walked away toward Charlotte Street for a brief
1 There was testimony at trial that the time stamps on the security camera footage were seven minutes fast. We refer to the actual time, rather than the time stamp indicated on the footage.
2 We refer to Tevan Williams by his first name to avoid confusion with Keith Williams, the defendant. There is no relation between them.
5
period after his exit from the store, and, while he was gone, a
brief argument occurred between Tevan and Reed. Reed, Joyce,
and their two companions then walked away from the store in the
opposite direction, toward McLellan Street, followed seconds
later by Tevan and Colas upon Colas's return.
Shortly after the two groups walked away from the store
down Blue Hill Avenue toward McLellan Street, Colas pulled out a
silver handgun from his waistband and pointed it toward the
group that included Reed and Joyce, farther down the avenue
toward McLellan Street. The defendant -- who inferably had
rejoined Reed and Joyce by this time -- then fired at least five
bullets in the direction of Colas and Tevan.3 The defendant,
Reed, and Joyce ran away down McLellan Street.
The defendant's bullets did not hit Colas or Tevan but did
strike two bystanders. One bullet fatally struck the head of
Jaffier as she walked across the street with two friends.
Another struck Fulton in the leg as she sat watching the parade
from the avenue's median strip.
One witness to the shooting, Amanda Griffith, observed that
the shooter was the largest of the three men running from the
3 Witnesses at the scene testified to hearing as many as five shots, and the recovered firearm contained six empty rounds. One of the bullets and fragments of a second were recovered.
6
scene after the shooting. The defendant was distinctly taller
and larger around the waist than Reed or Joyce.
A second account of the shooting came from Brenda Robinson,
who was walking with a three year old child on Blue Hill Avenue,
had just crossed McLellan Street, and was proceeding along the
avenue toward Charlotte Street. She saw a man farther down the
block in front of a barbershop, inferably Tevan, start jumping
up and down and yelling "blast, blast." As Robinson leaned down
to pick up the child, she was pushed against a gate by a man,
inferably the defendant, who felt "heavy." He leaned on her as
he shot at Colas and Tevan.
Lashonda Osorio, who lived in a side-street apartment
approximately 500 feet from the intersection of Blue Hill Avenue
and McLellan Street, heard the gunshots. She went to her window
and saw the defendant, Reed, and Joyce walking down the street
acting "nervous." She heard Reed tell the defendant to "get rid
of it." Osorio then watched as the defendant went to the house
across the street from her apartment and disposed of a firearm.
As the three left the area, Reed told the defendant to "[w]alk,
don't run, walk."
Osorio alerted police to what she had seen. She gave
descriptions of each of the three men matching the defendant,
Reed, and Joyce. Shortly thereafter, police recovered a .357
revolver from under the porch of the house to which Osorio
7
directed them. The revolver contained six empty shell casings.
Ballistic testing later revealed that the weapon fired the
bullets that killed Jaffier and injured Fulton.
Police stopped and handcuffed the defendant, Reed, and
Joyce a short distance away. Police eventually arrested them,
brought them to police headquarters, and collected samples from
their hands in order to test for gunshot residue particles.
Later, the defendant's T-shirt also was tested.
As we shall discuss in greater detail, the results for the
gunshot residue tests of the defendant, Reed, and Joyce all were
negative; no sample had the minimum of three gunshot residue
particles necessary to qualify as a positive test result.
However, one gunshot residue particle was detected in one of the
samples taken from the defendant's hands, and another particle
was detected in a sample from his T-shirt. No gunshot residue
particles were found in the samples from Reed and Joyce.
The defendant waived his rights under the Fifth Amendment
to the United States Constitution and gave a statement to
police. He admitted to having been dropped off near the
location of the shooting about an hour before it occurred but
denied possessing or disposing of a gun and also claimed he had
not been to the convenience store that morning.
2. Defense. The defense at trial was that the defendant
was not the shooter. Trial counsel emphasized that no witness
8
positively identified the defendant as the shooter, despite what
counsel argued was a conspicuous appearance. The defendant was
at least six feet tall and was described as "a big guy" and
"heavy set." On the day of the shooting, he was wearing a
bright blue T-shirt with green cartoon characters on the front,
blue shorts, and bright blue and orange sneakers.
Among the witnesses who did not notice the defendant at the
scene was off-duty Detective Arthur Hall-Brewster, who was
waiting outside the barbershop at the scene of the shooting. He
testified that working for decades as a detective had given him
the habit of taking note of his surroundings, and he noticed the
young men walking in and out of the convenience store, including
Colas, Tevan, Reed, and Joyce. He testified that some of the
men he saw, including Reed and Joyce, had their hands in their
waistbands, which made him believe that they might be armed. He
sensed tension between the groups outside the store, saw Colas
with a gun, and heard gunshots. He did not see the defendant,
however.
As described above, Robinson felt the "heavy" shooter lean
over her, but she was not able to see or describe the shooter's
appearance, and the Commonwealth's witnesses who did see the
shooter gave varying descriptions that, the defendant argued,
were inconsistent with his own appearance. Griffith, the
witness who characterized the shooter as the largest of the
9
three men running from the scene, also described the shooter as
about five feet, eight or nine inches tall, not heavy set, and
wearing a green shirt and dark pants. Troy Souto, who lived on
the block and also witnessed the shooting, described the shooter
as having a "slinky stocky" build, which he defined as having
muscular shoulders and a thin waist.
The sole witness called by the defense, Akeisha Lewis, gave
a description of the shooter that was consistent with Reed, not
the defendant. Lewis was walking along Blue Hill Avenue with
her cousin after the parade and saw a group of men arguing at
the corner of McLellan Street and Blue Hill Avenue. Thereafter,
a man wearing black pants and a white shirt with black sleeves
fired a gun. On the day of the shooting, Reed was wearing black
pants and a white sleeveless tank top with a black shirt wrapped
around his neck and shoulder area.
The defendant also argued that no forensic evidence tied
him to the shooting. Tests conducted on the revolver for
deoxyribonucleic acid (DNA) and fingerprints were inconclusive.
And, as mentioned, the gunshot residue tests of the defendant's
hands and shirt yielded negative results.
3. Prior proceedings. On November 19, 2014, a grand jury
indicted the defendant for murder, G. L. c. 265, § 1; armed
assault with intent to murder, G. L. c. 265, § 18 (b); assault
and battery by means of a dangerous weapon, G. L. c. 265,
10
§ 15A (b); and carrying a firearm without a license, G. L.
c. 269, § 10 (a).
Prior to trial, the Commonwealth moved to admit in evidence
expert testimony that one gunshot residue particle was detected
in a sample taken from the defendant's hands and another
particle in a sample from his T-shirt. The Commonwealth
acknowledged that its expert would testify that the test results
were negative due to the failure to detect the minimum of three
particles. Nonetheless, citing Commonwealth v. Johnson, 463
Mass. 95, 108 (2012), the Commonwealth sought admission of
testimony regarding the one particle in each sample in order to
argue to the jury that they should infer from the detection of
the particles that the defendant was the shooter.
The defendant opposed the Commonwealth's motion. The
defendant argued that the Commonwealth in essence was attempting
to use the evidence regarding the one gunshot residue particle
in each sample as a positive test result despite the fact that,
under the applicable laboratory guidelines, the results were
negative. The defendant further argued that detection of the
particles could have been the result of contamination, and that
any probative value of this evidence was substantially
outweighed by the risk of unfair prejudice.
In support of these arguments, the defendant submitted
various materials. A copy of the negative test results for his
11
shirt stated that "no conclusions can be made as to whether [the
shirt] may have been in the vicinity of a firearm when it was
discharged, or may have come into contact with an item with
[g]unshot [p]rimer [r]esidue on it." A Boston police department
policy on gunshot residue testing stated, among other things,
that although gunshot residue particles may be reliably
identified, "it is not yet possible to assess scientifically the
significance of such an identification"; that the department had
a policy not to perform such testing; and that, if an
investigator nonetheless wished to collect such evidence, crime
laboratory personnel could collect it, with testing to be
performed by another facility.4 Collection guidelines provided
that "[s]ampling on hands must be performed within [four] hours
of the shooting incident," with the "best practice" being
collection "at the scene or as expeditiously as possible" and
"before the subject is placed into handcuffs or . . . a police
vehicle." A published summary of a Federal Bureau of
Investigation symposium on gunshot residue described, among
other things, experts' views and research showing that gunshot
residue particles may be transferred onto a test subject through
4 After oral argument in this court, the Commonwealth submitted a letter reporting that, since the time of trial, the Boston police department has changed its policy, and its crime laboratory now conducts gunshot residue testing.
12
contact with armed law enforcement officers, handcuffs, and
police vehicles. And an affidavit from the defendant described
the timing of the gunshot residue testing, more than three and
one-half hours after he was stopped by police, and where and how
he had been detained and transported in the intervening hours.
After taking the matter under advisement, the judge allowed
the Commonwealth's motion to admit the expert testimony, subject
to the Commonwealth laying an "appropriately detailed
foundation" regarding gunshot residue. Citing Johnson, 465
Mass. at 108-109, the judge concluded that the risk of unfair
prejudice from the evidence was not outweighed by its "potential
probative value"; that the defendant's arguments went to the
weight of the evidence and could be explored on crossexamination; and that the jury would decide what inferences, if
any, to draw from the evidence. The disputed expert testimony
then was admitted in evidence at trial, and the Commonwealth
relied on it in closing argument to argue that the defendant was
the shooter.
On December 28, 2017, the jury found the defendant guilty
of murder in the first degree on the theory of deliberate
premeditation and also guilty on the other offenses with which
he was charged.5 The defendant's direct appeal was stayed while
5 The jury also found the codefendant Colas guilty of deliberately premeditated murder in the first degree and other
13
he filed a motion for a new trial. The motion sought relief on
grounds including error in the admission in evidence of the
number of gunshot residue particles detected in the negative
test results; various claimed improprieties in the prosecutor's
opening statement and closing argument; and insufficient
evidence of deliberate premeditation. The motion judge, who was
not the trial judge, ultimately denied the motion without an
evidentiary hearing.6 We consolidated the defendant's appeal
from that order with his direct appeal.
offenses. See Commonwealth v. Colas, 486 Mass. 831, 832 (2021). We vacated Colas's convictions of murder and armed assault with intent to murder for insufficient evidence of intent to kill and remanded the case for a new trial on so much of the indictment as alleged murder in the second degree. See id. at 846.
6 The motion judge initially granted an evidentiary hearing on a claim in the defendant's motion for a new trial that testimony from a percipient witness, Damon Stallings, was newly discovered evidence that would have been a real factor in the jury's deliberations. Stallings, who did not testify at trial, stated in an affidavit that he was one of the individuals depicted in the convenience store security footage with Reed and Jordan on the morning of the shooting; that Reed, not the defendant, brought a gun to the parade and fired it; and that Stallings previously had been too afraid to give police this information. After the evidentiary hearing was scheduled, the defendant gave notice that Stallings had become uncooperative and the defendant no longer intended to present evidence at the hearing, and the hearing was canceled. The defendant does not argue on appeal that his motion should have been allowed on this ground. He does continue to press on appeal the additional claim raised in his motion that he received ineffective assistance of counsel at trial because counsel failed to pursue a self-defense theory or any mitigation defense. He also argues for the first time on appeal that the prosecutor elicited inadmissible testimony from two witnesses. Deciding this case as we do, we need not address these claims.
14
Discussion. We first address the defendant's argument
regarding the gunshot residue evidence and then turn to his
sufficiency argument.
1. Gunshot residue particles. The defendant argues that
the expert testimony regarding the detection of two gunshot
residue particles in his negative test results should not have
been admitted as evidence that he was the shooter.7
a. Evidence. At trial, the Commonwealth presented its
gunshot residue evidence through the testimony of Jacqueline
Massua, the Boston police department criminalist who collected
the gunshot residue evidence from the hands of the defendant,
Reed, and Joyce on the day of the shooting, and John Drugan of
the State police crime laboratory, who performed the gunshot
residue testing and testified as an expert regarding such
testing. We summarize their testimony.
Gunshot residue particles are released in a vapor cloud
when a firearm is fired. A particle of gunshot residue consists
of three components not generally found together as one particle
in nature: barium nitrate, lead styphnate, and antimony
7 In connection with his motion for a new trial, the defendant submitted, among other things, an expert affidavit in support of his argument that this testimony should not have been admitted. Because we conclude, based on the record as it stood at trial, that it was error to admit this testimony and that the error was prejudicial, we need not consider the additional arguments and materials presented in the posttrial motion.
15
sulfide. A person may have gunshot residue on his or her hands
if the person "recently fired a gun, handled a firearm, [was] in
the presence of a gunshot, [was] handcuffed by someone who has
recently handled a firearm, . . . [or] touched an area where
firearms are routinely found."
To test for the presence of gunshot residue particles, a
stub -- essentially, an adhesive tape -- is applied to a surface
such as a hand or piece of clothing, and the stub then is
examined for gunshot residue particles using a scanning electron
microscope. Under scientific standards established by the
Federal Bureau of Investigation and the Massachusetts State
Police, a positive gunshot residue test requires the detection
of three or more gunshot residue particles, a threshold Drugan
referred to as the "three-component, three-particle threshold."
Individual particles found in separate tests cannot be "added
up" to meet this three-particle threshold.
In this case, Massua stubbed the hands of the defendant at
11:53 A.M. on the morning of the shooting, which had occurred at
approximately 8:16 A.M., and also stubbed the hands of Reed and
Joyce. A police officer collected the defendant's T-shirt the
following day for testing, and a different criminalist stubbed
it for gunshot residue thirteen months later. Drugan
subsequently tested the stubs for the presence of gunshot
residue. Each stub tested negative.
16
Drugan further testified regarding the number of gunshot
residue particles underlying the negative test results for the
defendant, Reed, and Joyce. No particles of gunshot residue
were found on the stubs taken from the hands of either Reed or
Joyce. One gunshot residue particle was found on one stub from
the defendant's hands, and another was found on the stub from
his T-shirt. Drugan explained that, despite the single gunshot
residue particle found on each of these stubs from the
defendant, both tests nonetheless were negative results because
the number of gunshot residue particles fell below the "threecomponent, three-particle threshold."
On cross-examination, Drugan agreed that there was "nothing
to be drawn from" the negative test results. Drugan's reports
of the results of his analyses, which were admitted in evidence
over the Commonwealth's objection, similarly stated that,
because the test results for the defendant, Reed, and Joyce each
were negative, "no conclusions can be made as to whether these
individuals may have discharged a firearm, may have been in the
vicinity of a firearm when it was discharged, or may have come
into contact with an item with [gunshot residue] on it." Drugan
agreed that the three-particle threshold is in place in part to
account for the possibility of contamination and to assure
accurate interpretation of test results. He further testified
that microscopic particles of gunshot residue are resilient and
17
transferable and are known to persist on handcuffs and surfaces
inside of police cruisers and stations.
b. Standard of review. "We review a judge's determination
to admit or exclude expert testimony . . . for an abuse of
discretion." Commonwealth v. Rintala, 488 Mass. 421, 425
(2021), quoting Commonwealth v. DiCicco, 470 Mass. 720, 729
(2015). "The defendant must therefore demonstrate that the
judge 'made a clear error of judgment in weighing the factors
relevant to the decision, such that the decision falls outside
the range of reasonable alternatives.'" Rintala, supra at 425-426, quoting L.L. v. Commonwealth, 470 Mass. 169, 185 n.27
(2014). "Although 'our review under this standard is
deferential and limited, it is not perfunctory. A judge's
findings must apply the correct legal standard to the facts of
the case and must be supported by an examination of the
record.'" Commonwealth v. Hinds, 487 Mass. 212, 218 (2021),
S.C., 494 Mass. 681 (2024), quoting Commonwealth v. Patterson,
445 Mass. 626, 639 (2005).
Where a defendant has preserved at trial the evidentiary
error claimed on appeal, the defendant "need only demonstrate
that any error was prejudicial to warrant reversal." Rintala,
488 Mass. at 426. An error is prejudicial unless we can say
that it "did not influence the jury, or had but a slight
effect." Hinds, 487 Mass. at 229, quoting Commonwealth v.
18
Pfeiffer, 482 Mass. 110, 129, cert. denied, 589 U.S. 1061
(2019). See Rintala, supra at 444 (Commonwealth must show "with
fair assurance . . . that the judgment was not substantially
swayed" by error [citation omitted]).
c. Admissibility. "The role of expert testimony is to
assist jurors in interpreting evidence that lies outside of
their common experience." Hinds, 487 Mass. at 217, quoting
Commonwealth v. Shanley, 455 Mass. 752, 761 (2010). See
Commonwealth v. Torres, 469 Mass. 398, 406 (2014), quoting Mass.
G. Evid. § 702 (2014) (expert testimony must "assist the trier
of fact to understand the evidence or to determine a fact in
issue"). Admission of expert testimony is governed by the
standard under Daubert v. Merrell Dow Pharms., Inc., 509 U.S.
579, 593-594 (1993), as adopted by this court in Commonwealth v.
Lanigan, 419 Mass. 15, 26 (1994).8 See Commonwealth v. Davis,
487 Mass. 448, 453 (2021), S.C., 491 Mass. 1011 (2023). "Under
the Daubert-Lanigan standard, 'the touchstone of admissibility
8 Expert testimony also may be admitted under the standard set forth in Frye v. United States, 293 F. 1013, 1014 (D.C. Cir. 1923). See Davis, 487 Mass. at 453-454, and cases cited (Frye standard requires expert's theory and methodology to be generally accepted by relevant scientific community). Here, the Commonwealth did not attempt to establish that the number of particles detected in negative gunshot residue tests has gained general acceptance in a relevant scientific community as evidence that the tested person fired a weapon -- a proposition contrary to the testimony of the Commonwealth's own expert that nothing could be drawn from the negative test results.
19
is reliability.'" Hinds, supra at 220, quoting DiCicco, 470
Mass. at 729. Accordingly, the judge, as gatekeeper of the
evidence, "must make a threshold determination that the
testimony is both relevant and 'sufficiently reliable to go
before the jury.'" Hinds, supra at 218, quoting Commonwealth v.
Hoose, 467 Mass. 395, 417 (2014).
The proponent of expert testimony therefore must lay a
foundation from which the judge can make this threshold
determination as to the reliability of the testimony. See
Davis, 487 Mass. at 453. The proponent "must establish, among
other factors, that the testimony is . . . based on a reliable
methodology, and that the methodology 'is applied to the
particular facts of the case in a reliable manner.'" Hinds, 487
Mass. at 220, quoting Commonwealth v. Barbosa, 457 Mass. 773,
783 (2010), cert. denied, 563 U.S. 990 (2011), and citing Mass.
G. Evid. § 702 (2021).9 "Because different subject matters allow
for varying degrees of certainty, the metrics used to assess
reliability understandably vary across areas of expertise."
9 In assessing the reliability of the methodology underlying the expert testimony under the Daubert-Lanagan standard, "[t]he five nonexclusive factors are whether the scientific theory or process (1) has been generally accepted in the relevant scientific community; (2) has been, or can be, subjected to testing; (3) has been subjected to peer review and publication; (4) has an unacceptably high known or potential rate of error; and (5) is governed by recognized standards" (quotation omitted). Rintala, 488 Mass. at 437 n.30, quoting Davis, 487 Mass. at 454.
20
Hinds, supra at 221. See, e.g., Commonwealth v. Pytou Heang,
458 Mass. 827, 848-849 (2011), and cases cited (admission of
ballistician's opinion "to a 'reasonable degree of ballistic
certainty'").
"An evidentiary Daubert-Lanigan hearing is generally not
required where we have previously admitted expert testimony of
the same type, where the testimony is offered for the same
purpose, and where there is no factual issue as to whether the
expert is qualified, whether the appropriate methodology has
been followed, or whether the quality of the evidence is
sufficient to permit an opinion." Pytou Heang, 458 Mass. at
845. However, we have not foreclosed challenges to "any
particular theories or methods for all time, especially in areas
where knowledge is evolving, and new understandings may be
expected as more studies and tests are conducted." Shanley, 455
Mass. at 763 n.15, citing Lanigan, 419 Mass. at 26-27.
Moreover, as already mentioned, "evidence can only be
admitted if, in addition to the reliability of the theory and
process in general, the process is reliable when applied to the
specific issue about which the expert is proposing to testify."
Patterson, 445 Mass. at 645, citing Kumho Tire Co. v.
Carmichael, 526 U.S. 137, 153-154 (1999). See Kumho Tire Co.,
supra ("specific issue before the court was not the
reasonableness in general" of expert's method but instead
21
"reasonableness of using such an approach . . . to draw a
conclusion regarding the particular matter to which the expert
testimony was directly relevant"). See also Commonwealth v.
Honsch, 493 Mass. 436, 450 (2024) ("The Commonwealth must show
not only that the methodology is reliable, but also that the
particular application of that process is reliable"). "Judges
. . . need not admit . . . every application of a testing method
-- no matter how dubious -- merely because another application
of the method has been deemed reliable. Otherwise, the
traditional role of judges as gatekeepers -- protecting juries
from evidence that had little chance of being reliable -- would
be significantly and needlessly diminished." (Citations
omitted.) Patterson, supra at 648.
In Davis, 487 Mass. at 456, for example, which concerned a
particular application of global positioning system (GPS)
technology, it was "clear from both the record and our case law
that GPS technology is generally accepted as reliable" for
purposes of establishing location. Rather than just using the
GPS technology to establish location, however, the expert in
Davis testified that data from a GPS monitoring device worn by
the defendant showed that the defendant's speed matched the
speed of the person who shot the victim. Id. at 449. We held
that admission of this evidence was error where the Commonwealth
made no showing that the device reliably measured the
22
defendant's speed; the Commonwealth had not shown, for example,
that the device had been tested or peer reviewed, nor that the
device applied the same methodology as some other device
previously found to be reliable. Id. at 457.
Here, the defendant does not dispute the admissibility of
gunshot residue evidence generally. Cf. Pytou Heang, 458 Mass.
at 850-851 (upholding admission of gunshot residue evidence).
Nor does he challenge the testimony at trial that the tests of
the defendant, Reed, and Joyce returned negative results.
Rather, the defendant solely challenges the admission in
evidence of expert testimony regarding the number of gunshot
residue particles detected in his negative test results as proof
that he was the shooter. Among other arguments, the defendant
contends, citing Barbosa, 457 Mass. at 783, and Mass. G. Evid.
§ 702 (2025), that contrary to the requirement that expert
testimony be the product of a reliable methodology that has been
reliably applied to the facts of the case, the Commonwealth's
offer in evidence of the underlying gunshot residue particles as
proof that the defendant was the shooter was not supported by
the scientific standards that informed that expert's testimony.
The Commonwealth's brief does not address reliability, instead
arguing more generally, as the Commonwealth did at trial, that
the jury were entitled to infer culpability based on detection
of one particle in each of two samples taken from the defendant
23
under Johnson, 463 Mass. at 108-109, and that the defendant's
objections to the evidence "are subjects for cross-examination
that bear on the weight of the evidence" rather than its
admissibility, Commonwealth v. Sicari, 434 Mass. 732, 751
(2001), cert. denied, 534 U.S. 1142 (2002).
We agree with the defendant that, on this record, the
Commonwealth did not meet its threshold burden, as the proponent
of the evidence, to establish that the detection of one gunshot
residue particle in each of two negative test results for the
defendant was reliable evidence that the defendant fired the
murder weapon -- the contested issue with respect to which the
Commonwealth offered the evidence -- or of any other material
issue at trial. See Davis, 487 Mass. at 453. The
Commonwealth's expert opined at trial, consistent with his
statement on the negative test results that were before the
judge at the hearing on the Commonwealth's motion to admit the
evidence, that nothing could be drawn from the results. The
expert also testified, again consistent with materials the
defendant submitted at the hearing on the Commonwealth's motion,
that the three-particle threshold for a positive test result
exists in part due to the risk of contamination and the need to
ensure accurate interpretation of the results. The Commonwealth
did not offer any evidence that, notwithstanding the view of its
own expert, the detection of one particle in each of the
24
negative test results reliably tended to prove that the
defendant had fired the gun, or any other material issue at
trial. While "the metrics used to assess reliability
understandably vary across areas of expertise," Hinds, 487 Mass.
at 221, here the Commonwealth offered no metric for assessing
the reliability of the expert's testimony about the gunshot
residue particles as proof of a material fact in this case.10
The Commonwealth was not relieved of its burden to
establish the reliability of its expert's testimony by our
decision in Johnson, 463 Mass. at 108-109. There, the
Commonwealth's expert testified without objection that a glove
associated with the defendant tested positive for gunshot
residue and that, although the test results for a sweatshirt
also associated with the defendant were negative, two particles
were detected on the sweatshirt. Id. at 106-107. On appeal,
10In this regard, the Commonwealth's evidence differed from the evidence in cases in which other States' highest courts have found no error in the admission of test results falling short in some respect from a positive result for three-component gunshot residue particles. See, e.g., State v. Williams, 350 Conn. 363, 384-392 (2024) (no error in admission of test results showing presence of particles containing only one or two of the three elements of gunshot residue, where expert testified results were "commonly associated with" or "consistent with" gunshot residue); Mills v. State, 476 So. 2d 172, 176 (Fla. 1985) (no error in admission of testimony that defendant's test "was positive in that it revealed the presence of antimony in an amount not to be expected on a person who had not fired a gun, although it was not enough to prove conclusively that he had done so").
25
the defendant in Johnson newly raised two arguments against
admission of this evidence. First, he argued that gunshot
residue analysis in general was "'junk' science," a claim we
rejected on the ground that he had not provided evidence to
undermine our conclusion in Pytou Heang, 458 Mass. at 850-851,
that gunshot residue testing can serve as probative evidence.
Johnson, supra at 107. Second, he argued that the testimony
about the two gunshot residue particles detected on his
sweatshirt was false testimony in violation of his due process
rights. See id. at 107. We rejected this argument because the
expert's testimony in fact was not false; two particles had been
detected. Id. at 107-108. We further stated, based on the
limited record, that the jury were entitled to infer a greater
likelihood of culpability from the presence of the two
particles. See id. at 108-109. We said nothing, however, to
the effect that such evidence of a number of particles that
fails to clear the scientific threshold required for a positive
test result has been generally accepted as reliable proof that a
person fired a gun, cf. Shanley, 455 Mass. at 763 n.15, let
alone to foreclose future challenges based on advances in
science or simply a more developed record, see Johnson, supra at
107-109. Johnson thus did not establish that the detection of
particles below the scientific threshold for a positive result,
standing alone and without any showing as to its reliability to
26
prove as much, necessarily supports an inference that the tested
person fired a gun. To the extent Johnson may be read to
suggest otherwise, we disavow that suggestion.
Thus, the Commonwealth here was obliged to establish that
the detection of one gunshot residue particle in each of two
negative test results was reliable evidence to support the
inference that the defendant, rather than his companions, fired
the weapon. See Hinds, 487 Mass. at 220. Because the
Commonwealth failed to provide that foundation, the expert
testimony regarding the underlying gunshot residue particles
should not have been admitted for that purpose. See Davis, 487
Mass. at 457. To be sure, we do not hold that expert testimony
regarding the detection of a below-threshold number of gunshot
residue particles necessarily is categorically inadmissible in
all cases. Rather, the admissibility of expert testimony
regarding matters outside jurors' common experience depends on
the foundation offered and the inference for which the evidence
is introduced, see Hinds, supra at 217-218, citing Daubert, 509
U.S. at 597, and here the Commonwealth failed to establish a
sufficient foundation in support of the inference it asked the
jury to draw.
In so holding, we emphasize that this is not a case where
the Commonwealth offered evidence shown to be reliable even if
"not definitive." Torres, 469 Mass. at 407. In appropriate
27
circumstances, expert testimony may be admissible even where not
definitive. See, e.g., id. at 407-408 (while expert gave only
qualified opinion that defendant's shoe "'could have' made"
bloody shoeprint, "the expert led the jury through the factors
he applied in his analysis," and there was "no suggestion in the
record that a proper analysis require[d] a particular 'score'
among the four factors"). See also Commonwealth v. Linton, 483
Mass. 227, 241-242 (2019) (proponent of DNA result falling short
of minimum threshold sufficiently demonstrated through expert
testimony that below-threshold result nonetheless "provide[d]
relevant data, and [could] be used to support an exclusion,"
unlike in DiCicco, 470 Mass. at 731, where proponent proffered
no evidence to establish reliability of below-threshold result).
In Commonwealth v. McNickles, 434 Mass. 839, 854-855 (2001), for
example, we held that certain DNA evidence was properly admitted
where, although "not presented to the jury as a complete
identification or as a 'match,'" the evidence "provided at least
some reliable information about the perpetrator that was
admittedly consistent with the defendant and that excluded two
other possible suspects." Here, although the Commonwealth
somewhat analogously sought to use the subthreshold gunshot
residue particles detected in the negative test results as
evidence that the defendant, rather than his two companions, was
the shooter, the Commonwealth failed to meet its initial burden
28
to show that detection of these particles reliably supported
that inference. Indeed, the only evidence on this point was the
contrary statement by the Commonwealth's own expert that no
inference at all could be drawn.
d. Prejudice. The Commonwealth has not argued that, even
if the testimony regarding the subthreshold number of gunshot
residue particles was admitted in error, the defendant is not
entitled to a new trial. Indeed, a new trial is required.
The disputed gunshot residue testimony figured prominently
in the Commonwealth's case. In the Commonwealth's opening
statement, the prosecutor explained that gunshot residue
particles were found on the defendant, without mentioning that
the particles did not amount to a positive test result. In
closing argument, the prosecutor acknowledged that the test
results were negative, but told the jury that the threshold for
a positive result was "not [their] protocol," and that they
could "interpret [the evidence] however [they] want," because
"[t]hat's not a jury standard of practice, that's a
Massachusetts State Police standard of practice." The
prosecutor then highlighted that gunshot residue particles were
found only in the samples taken from the defendant, not Reed or
Joyce, and urged the jury to rely on this evidence to conclude
that the defendant was the shooter. The prosecutor's closing
also undercut the defendant's attempt to minimize this evidence
29
-- through an argument, based on cross-examination of the
Commonwealth's witnesses, that the particles could be the result
of contamination -- by pointing out that Reed and Joyce too had
been handcuffed, transported in police vehicles, and detained
for hours prior to the testing, and yet no particles were found
in their negative test results. This thus is not a case where,
although evidence was admitted in error, the Commonwealth
refrained in its closing argument from arguing that the jury
should rely on it. Contrast, e.g., Commonwealth v. Nesbitt, 452
Mass. 236, 255 (2008).11
11The defendant also points out that the Commonwealth's closing argument contained a misstatement regarding the gunshot residue evidence. The prosecutor stated that, under the Massachusetts State police testing protocols, "to call it positive we need two particles." The testimony instead was that three particles from a single sample were required. Deciding the case as we do, we need not address this issue nor most of the other claimed improprieties in the prosecutor's opening statement and closing argument, all of which went without objection by the defendant at trial, and we assume that any impropriety will not be repeated in a second trial.
Because one issue raised by the defendant is likely to reoccur at any retrial, however, we address it briefly. The defendant argues that the prosecutor impermissibly used gang innuendo in his opening statement by referring to the group of men associated with the defendant who walked into the convenience store together as "team Williams." The prosecutor noted for the jury that this descriptor was "[f]or purposes of this opening statement"; otherwise, the prosecutor would have had to repeat the names or descriptions of multiple individuals in narrating how the events unfolded. There was no error in these references. See Commonwealth v. Brown, 477 Mass. 805, 818 (2017) (no error in describing defendant as part of team to help jury understand Commonwealth's theory).
30
Moreover, the Commonwealth's evidence identifying the
defendant as the shooter was not overwhelming. The Commonwealth
did introduce evidence that the defendant was with Reed and
Joyce mere seconds after the shooting, holding the murder
weapon; that the defendant then disposed of the murder weapon;
that one witness described the shooter as being the largest of
the three men fleeing the scene, as was true of the defendant by
comparison with Reed and Joyce; that another witness described
physical contact with a "heavy" shooter; and that, on being
detained shortly after the shooting, the defendant made two
statements from which the jury could infer consciousness of
guilt, because the statements were contradicted by other
evidence. However, the defendant was not seen in the area
immediately before the shooting and was not present with Reed
and Joyce during the tense encounter in the convenience store or
the argument outside the store; no witness or forensic test
positively identified him as the shooter; and the witness whose
description of the shooter was the strongest for the
Commonwealth's case -- because she testified that the shooter
was the largest of the three men fleeing the scene -- also
described several other details of the shooter's appearance that
were not consistent with the defendant. Additionally, another
witness's description of the shooter matched Reed's appearance;
one witness had made observations prior to the shooting leading
31
the witness to believe Reed was armed; and the witness who saw
the defendant dispose of the gun heard Reed in command,
directing the defendant's actions.
In these circumstances, we cannot conclude that the error
"did not influence the jury, or had but a slight effect"
(citation omitted). Hinds, 487 Mass. at 229. The defendant
therefore is entitled to a new trial on the charges of murder in
the first degree, armed assault with intent to murder, and
assault and battery by means of a dangerous weapon.
2. Sufficiency of evidence. We next address the
defendant's argument that there was insufficient evidence that
he acted with deliberate premeditation, such that he may not be
retried for murder in the first degree. "Because the defendant
challenges the sufficiency of the evidence as to one element
only -- deliberate premeditation -- we examine the sufficiency
of evidence relevant to that element alone."12 Commonwealth v.
Gambora, 457 Mass. 715, 732 (2010), quoting Commonwealth v.
Coleman, 434 Mass. 165, 167 (2001). We thus must determine
whether, "viewing the evidence in the light most favorable to
the Commonwealth, any rational jury could have found deliberate
12At trial, the defendant argued that the evidence was not sufficient to identify him as the shooter. He does not press this argument on appeal, and, having reviewed the full record of the case pursuant to our duty under G. L. c. 278, § 33E, we discern no substantial likelihood of a miscarriage of justice on this ground.
32
premeditation beyond a reasonable doubt." Gambora, supra.
"[C]ircumstantial evidence is sufficient to establish guilt
beyond a reasonable doubt, and inferences drawn from such
evidence need only be reasonable and possible; [they] need not
be necessary or inescapable" (quotation and citations omitted).
Commonwealth v. Gonzalez, 475 Mass. 396, 407 (2016). However,
"[n]o[] . . . conviction [may] rest upon the piling of inference
upon inference or conjecture and speculation." Id., quoting
Commonwealth v. Swafford, 441 Mass. 329, 343 (2004).
"In order to prove deliberate premeditation, the
Commonwealth must show that the plan to kill was formed after
deliberation and reflection" (quotation and citation omitted).
Commonwealth v. Bolling, 462 Mass. 440, 446 (2012). "[N]o
particular length of time is required in order for deliberate
premeditation to be found," however, as "a decision to kill may
be formed in a few seconds" (citations omitted). Id.
Accordingly, "it is the sequence of the thought process rather
than the time which is taken to think that is the key to
determining whether someone acted with deliberate
premeditation." Commonwealth v. Fernandez, 480 Mass. 334, 345
(2018), quoting Commonwealth v. Chipman, 418 Mass. 262, 269
(1994).
The evidence here would allow a rational jury to find
beyond a reasonable doubt that the defendant acted with
33
deliberate premeditation based on the defendant's conduct at the
scene of the shooting. As already described, the defendant was
captured on surveillance footage outside the store with Reed and
Joyce less than an hour before the shooting, and then was seen
running from the scene with Reed and Joyce, holding the murder
weapon, mere seconds after the shooting. From eyewitness
accounts of the shooting, the jury could find that, after Colas
displayed and pointed a firearm toward the defendant and his
companions, the defendant made the decision to fire his own
weapon repeatedly at Colas. The defendant then fired at least
five rounds. Although the interval was brief, deliberate
premeditation may be formed in seconds, and the sequence of
conduct here permitted the jury to infer that the defendant
formed a decision to kill Colas before carrying it out by
repeatedly firing at him. See Bolling, 462 Mass. at 446. See
also Commonwealth v. Williams, 422 Mass. 111, 122-123 (1996),
and cited cases. The evidence of deliberate premeditation thus
was sufficient.
Conclusion. For the foregoing reasons, the defendant's
convictions are vacated and set aside, and this case is remanded
to the Superior Court for further proceedings consistent with
this opinion.
So ordered.