Case Title: Commonwealth v. Watt

Citation: 

Docket Number: 

State: massachusetts

Court: Massachusetts Supreme Court

Date: 2020-06-04T00:00:00Z

Document:
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revision and are superseded by the advance sheets and bound 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; SJCReporter@sjc.state.ma.us 
 
SJC-11693 
 
COMMONWEALTH  vs.  NYASANI WATT (and nine companion cases1). 
 
 
 
Suffolk.     December 10, 2019.  -  June 4, 2020. 
 
Present:  Gants, C.J., Gaziano, Lowy, Budd, & Cypher, JJ. 
 
 
Homicide.  Armed Assault with Intent to Murder.  Assault and 
Battery by Means of a Dangerous Weapon.  Firearms.  
Evidence, Expert opinion, Prior violent conduct, Relevancy 
and materiality, Firearm.  Constitutional Law, Sentence. 
Jury and Jurors.  Practice, Criminal, Capital case, Jury 
and jurors, Deliberation of jury, Assistance of counsel. 
 
 
 
 
Indictments found and returned in the Superior Court 
Department on December 21, 2011. 
 
 
The cases were tried before Christine M. Roach, J., and 
motions for a new trial, filed on November 25, 2014, April 4, 
2017, and June 21, 2017, were heard by her. 
 
 
Elizabeth Doherty for Nyasani Watt. 
Ruth Greenberg for Sheldon Mattis. 
Dara Z. Kesselheim, Assistant District Attorney, for the 
Commonwealth. 
Thomas H. Townsend & Jeanne M. Kempthorne, Assistant 
District Attorneys, for district attorney for the northwestern 
district & another, amici curiae, submitted a brief. 
Ryan M. Schiff, for Gary Johnson & another, amici curiae, 
submitted a brief. 
                     
 
1 Four against Nyasani Watt and five against Sheldon Mattis. 
2 
 
 
 
 
BUDD, J.  A jury in the Superior Court convicted the 
defendants, Nyasani Watt and Sheldon Mattis, of murder in the 
first degree, aggravated assault and battery by means of a 
dangerous weapon, and related offenses,2 in connection with a 
shooting that killed sixteen year old Jaivon Blake and injured 
fourteen year old Kimoni Elliott.  The defendants appeal from 
their convictions and from the denial of their motions for a new 
trial.  In addition, they ask us to exercise our authority under 
G. L. c. 278, § 33E, to order a new trial. 
 
After full consideration of the record and the defendants' 
arguments, we affirm the defendants' convictions and decline to 
grant either defendant extraordinary relief pursuant to G. L. 
c. 278, § 33E.  However, for the reasons discussed infra, we 
remand the issue of the constitutionality of Mattis's sentencing 
for an evidentiary hearing.3 
 
Background.  We summarize the facts the jury could have 
found, reserving certain details for discussion.  On September 
                     
 
2 The defendants also were convicted of armed assault with 
intent to murder, in violation of G. L. c. 265, § 18 (b); 
possession of a firearm without a license, in violation of G. L. 
c. 269, § 10 (a); and carrying a loaded firearm, in violation of 
G. L. c. 269, § 10 (n). 
 
 
3 We acknowledge the amicus brief submitted by Gary Johnson 
and Tyshawn Sanders; and the amicus letter submitted by the 
district attorney for the northwestern district and the district 
attorney for the Berkshire district. 
3 
 
25, 2011, Elliott was visiting Blake at Blake's home near the 
intersection of Geneva Avenue and Everton Street in the 
Dorchester section of Boston.  In the afternoon, Elliott walked 
from Blake's home to a nearby convenience store, located at the 
intersection of Geneva Avenue and Levant Street, to purchase 
rolling papers for marijuana cigarettes.  He waited outside the 
store looking for someone old enough to make the purchase.  An 
individual identified as Mattis approached on a bicycle and 
agreed to buy the rolling papers for Elliot.  After doing so, 
Mattis asked Elliott where he was from; Elliott replied, 
"Everton."  The two parted ways, and Elliott met Blake in a 
nearby parking lot. 
 
As Elliott and Blake began to walk toward Blake's home, 
they were shot from behind by a male riding a bicycle.  
Witnesses described the shooter as wearing jeans, a red shirt, 
and a baseball cap; clothes fitting these descriptions were 
later seized from the defendants' houses, and two witnesses 
described Watt as wearing similar clothing on the day of the 
shooting.  Blake suffered a single gunshot wound to the torso 
and died hours later at a hospital; Elliott survived gunshot 
wounds to his neck and right arm.  Hours later, Watt had changed 
his clothes, and a friend helped him to take the braids out of 
his hair so that he could "change his look."  Later that 
4 
 
evening, he, Mattis, and others were "celebrating because [of] 
something [Watt] did." 
 
Jeremiah Rodriguez, a key witness for the Commonwealth, 
testified that he, Watt, and Mattis were playing football on 
Levant Street in front of Rodriguez's house when they watched 
Elliott walk to the convenience store.  After Mattis went to the 
store to interact with Elliott, he returned to the area outside 
Rodriguez's house and said to Watt and Rodriguez, "[B]e easy, 
because that's them kids."  A few minutes later, Rodriguez 
observed Mattis meet with Watt at the corner of Levant Street 
and Geneva Avenue, hand Watt a gun, and pat him on the back.  
Rodriguez also testified that he heard Mattis tell Watt, 
"[T]hat's them walking up there right now" and that he "needed 
to go handle that."  Watt then rode away on the bicycle.  At 
trial, Rodriguez identified Watt in a surveillance video 
recording depicting him riding toward the scene of the shooting 
shortly before it occurred and wearing clothes generally 
matching eyewitness accounts of the shooter's appearance.  Soon 
thereafter, while on his back porch, Rodriguez heard gunshots. 
 
At trial, the Commonwealth's theory was that Watt and 
Mattis jointly planned and executed the shooting as part of an 
escalating gang feud.  The defendants' primary theories were 
misidentification of Watt as the shooter and the unreliability 
of Rodriguez's testimony establishing Mattis's participation. 
5 
 
 
The jury convicted both defendants of murder in the first 
degree on theories of deliberate premeditation and extreme 
atrocity or cruelty.  Watt, who was seventeen at the time of the 
shooting, received a life sentence with the possibility of 
parole after fifteen years.  Mattis, who was eight months older 
than Watt, and eighteen at the time, was sentenced to life 
imprisonment without the possibility of parole. 
 
Discussion.  1.  Direct appeal.  On direct appeal the 
defendants raise various evidentiary issues, assert error with 
respect to the jury instructions, and challenge the 
constitutionality of their sentences. 
a.  Evidentiary issues.  i.  Gang expert testimony.  To 
demonstrate that the motive for the shooting was gang-related, 
the Commonwealth presented the testimony of Detective Anthony 
Serra, who testified as both an expert and fact witness.  Serra 
testified about gang activity in the Dorchester area surrounding 
the scene of the shooting, and specifically about the "Flatline" 
gang, based on Levant Street, and the Geneva-Everton gang, based 
in the neighborhood where Blake lived.  He further testified 
that both defendants were associated with Flatline.  The 
defendants were unsuccessful in moving in limine to exclude the 
testimony and objected to it at trial.  On appeal, they argue 
that there was an inadequate basis for Serra to opine on the 
defendants' alleged membership in the Flatline gang and on the 
6 
 
alleged ongoing feud between Flatline and Geneva-Everton.4  We 
agree that the testimony should not have been admitted; however, 
we conclude that the error was not prejudicial.  See 
Commonwealth v. Sullivan, 478 Mass. 369, 375-376 (2017) 
(preserved issues reviewed for prejudicial error). 
Expert testimony must be based on "facts within the 
witness's direct personal knowledge, facts already introduced in 
evidence, or unadmitted but independently admissible evidence" 
(quotations and citation omitted).  Commonwealth v. Wardsworth, 
482 Mass. 454, 466 (2019).  See Mass. G. Evid. § 703 (2020).  
There is no indication that the basis for Serra's opinion fell 
into any of the above categories. 
First, Serra indicated that his opinion that the defendants 
were members of the Flatline gang was based on the "collective 
knowledge" of other officers in the Boston police department.  
Because it is impossible to ascertain from the record what 
                     
 
4 The defendants argue that the trial judge abused her 
discretion in qualifying Detective Anthony Serra as an expert 
witness.  However, they focus their arguments not on his 
qualifications as a gang expert, but on the basis for his 
opinion regarding the defendants' gang membership and Flatline's 
feud with Geneva-Everton.  We note that the detective's years of 
experience with the Boston police department in Dorchester, 
including on the youth violence strike force -- a subdivision of 
the department focused on youth and gang violence in the city -- 
are sufficient to qualify him to give general expert testimony 
about gangs in Dorchester.  Compare Commonwealth v. Barbosa, 477 
Mass. 658, 668 (2017) (detective qualified as expert on gang 
territory and history in specific section of Boston based on 
years of experience as officer in that section). 
7 
 
portion, if any, of such "collective knowledge" was based on 
personal observations that would have been independently 
admissible, Serra's opinion regarding the defendants' alleged 
gang membership improperly was admitted.  See Wardsworth, 482 
Mass. at 467-468 ("That other officers had formed the opinion 
that the defendant fit the criteria [for entry on the gang 
database] does not constitute proper foundation for [the 
expert's] opinion; the gang database entry did not provide [the 
expert] with underlying facts or data to which he could apply 
his own expertise"); Commonwealth v. Nardi, 452 Mass. 379, 392 
(2008) ("It is settled that an expert witness may not, under the 
guise of stating the reasons for his opinion, testify to matters 
of hearsay . . ." [quotation and citation omitted]). 
Serra's testimony regarding the alleged feud between the 
two groups similarly was inadmissible.  At trial, the detective 
explained that he first became aware of the feud when he heard 
about the fatal shooting of a resident of Geneva Avenue on New 
Year's Day in 2010.  Although he had personal experience with 
individuals from Levant Street who were arrested in connection 
with the shooting, he had no direct involvement with that 
incident.  He testified that his knowledge of the feud between 
Flatline and Geneva-Everton came from discussions with other 
investigators as well as residents in the area who provided tips 
and information.  Again, because there was no indication whether 
8 
 
this information, which formed the basis of his opinion, would 
have been independently admissible at trial, his opinion on this 
topic improperly was admitted.  See Wardsworth, 482 Mass. at 
466-471. 
Nevertheless, there was little, if any, prejudicial effect 
from this testimony.  Multiple civilian witnesses who lived on 
Levant Street and knew both defendants testified that the 
defendants were affiliated with the Flatline gang.  A friend of 
the defendants testified that Watt told her their group was 
called Flatline.  Another testified that Watt told him that 
"they" were called Flatline and that they "owned" Levant Street.  
Two other of the defendants' friends who testified recounted 
similar conversations with the defendants.  The number of 
witnesses testifying to this fact, combined with the witnesses' 
close friendship with the defendants, provided a strong case for 
the Commonwealth that the defendants were in fact members of the 
Flatline gang.  Several of the same witnesses also testified 
regarding the feud between Flatline and Geneva-Everton.  For 
example, one witness testified that both defendants told her 
that they had "problems with Geneva."  Another witness stated 
that Mattis told him that he had weapons because they had 
"drama," and "an issue going on now," which included Mattis 
previously having been beaten by members of a rival gang. 
9 
 
As the erroneously admitted expert testimony regarding the 
defendants' connection to Flatline and the feud between Flatline 
and Geneva-Everton was cumulative of similar admissible 
testimony, the errors were harmless.5  See Commonwealth v. Diaz, 
426 Mass. 548, 551-552 (1998) (inadmissible hearsay statement 
regarding defendant's state of mind cumulative of other properly 
admitted statements and therefore not prejudicial); Commonwealth 
v. Perez, 411 Mass. 249, 260-261 (1991) (erroneous admission of 
defendant's inculpatory statements harmless where cumulative of 
properly admitted evidence). 
 
ii.  Evidence of prior shooting.  Over the defendants' 
objection, the Commonwealth introduced evidence of a shooting on 
Levant Street that took place eleven days prior to the shooting 
of the victims.  The Commonwealth offered the evidence in 
support of its theory that the victims were shot in retaliation 
for the earlier incident.  On appeal, the defendants contend 
that admitting the evidence of the Levant Street shooting was 
error because the Commonwealth did not establish a connection 
between the two shootings.  We disagree. 
                     
 
5 Had the expert witness testified after the civilian 
witnesses testified to their knowledge of Flatline, the 
defendants' membership in it, and their feud with Geneva-
Everton, the expert's opinion on these issues likely would have 
been admissible, based on the facts already introduced in 
evidence.  See Mass. G. Evid. § 703(b) (2020). 
10 
 
We begin by noting that evidence of motive need not be 
conclusive to be admissible.  Commonwealth v. Ashley, 427 Mass. 
620, 624-625 (1998).  Rather, it need only provide a link in the 
chain of proof.  Commonwealth v. Gomes, 475 Mass. 775, 784 
(2016).  The evidence of the Levant Street shooting was relevant 
to show a motive for a shooting that otherwise appeared 
senseless.  See Commonwealth v. Walker, 460 Mass. 590, 613 
(2011).  The evidence connecting the two shootings included 
witness testimony that the defendants were members of the 
Flatline gang; that there was an ongoing conflict between the 
Flatline and Geneva-Everton gangs; that the location of the 
shooting was the headquarters of the Flatline gang; and that 
Elliot told Mattis that he lived on Everton Street just prior to 
the shooting.  Finally, the two shootings occurred just eleven 
days apart.6 
We further note that, because neither defendant was alleged 
to have been the shooter at the earlier shooting, there was no 
danger that the jury improperly would use the earlier shooting 
                     
6 The defendants contend that there was no evidence that the 
defendants knew (or believed) that the victims were members of, 
or affiliated with, the Geneva-Everton gang.  However, as 
mentioned supra, Kimoni Elliot testified that he told Mattis 
that he lived on Everton Street, which is part of the Geneva-
Everton gang's territory.  Although residing on a particular 
street is not by itself proof of gang membership, the jury could 
infer that the defendants believed that Elliot was affiliated 
with the Geneva-Everton gang because Elliot told Mattis that he 
lived on Everton Street. 
11 
 
as propensity or "bad act" evidence.  Compare Commonwealth v. 
Butler, 445 Mass. 568, 573-576 (2005).  Thus, although the 
evidence of the shooting was detrimental to the defendants' 
legal strategy, it was not unfairly prejudicial.  See 
Commonwealth v. Facella, 478 Mass. 393, 400-409 (2017).  See 
also Commonwealth v. Wall, 469 Mass. 652, 661 (2014) ("Relevant 
evidence is admissible as long as the probative value of the 
evidence is not substantially outweighed by the danger of unfair 
prejudice"); Commonwealth v. Keo, 467 Mass. 25, 32 (2014), 
quoting Commonwealth v. Smiley, 431 Mass. 477, 484 (2000).  The 
judge did not abuse her discretion in admitting evidence of the 
prior shooting. 
iii.  Firearm evidence.  Rodriguez testified that in the 
months preceding the shooting, both defendants possessed 
multiple firearms, including a "Glock" and a "40"; another 
witness testified that she saw Watt with a black gun during that 
same time period.  The jury also learned that Watt was in 
possession of a .38 caliber firearm when he was arrested.  On 
appeal, the defendants contend that the judge erred in admitting 
this evidence.  Because the defendants failed to preserve this 
issue, we review to determine if admission of this evidence was 
12 
 
error and, if so, whether it created a substantial likelihood of 
a miscarriage of justice.7 
It is true that evidence of other "bad acts," including the 
possession of firearms, is generally inadmissible to show one's 
propensity to commit a crime.  Commonwealth v. Vazquez, 478 
Mass. 443, 449 (2017).  See Commonwealth v. McGee, 467 Mass. 
141, 156 (2014).  However, evidence of other instances of 
firearm possession is nevertheless admissible to demonstrate, 
for example, preparation or opportunity as long as the probative 
value of the evidence is not outweighed by the risk of unfair 
prejudice to the defendant.  Vazquez, supra.  See Mass. G. Evid. 
§ 404(b)(2) (2020). 
The Commonwealth's ballistics expert testified that the 
weapon used in the shooting was a .40 caliber firearm; further, 
a percipient witness testified to seeing the gunman with a black 
firearm.  Thus, testimony that the defendants previously had 
been seen with a "Glock," a "40," and a black firearm was 
properly admitted to demonstrate that the defendants had access 
                     
7 The defendants raised this issue via motions in limine but 
did not object at trial.  The trial preceded Commonwealth v. 
Grady, 474 Mass. 715, 718-719 (2016), in which we held that 
counsel need not object at trial to preserve their objection to 
the admission of evidence argued in motions in limine.  Because 
Grady does not apply retroactively, we review the defendants' 
claims to determine whether any error resulted in a substantial 
likelihood of a miscarriage of justice.  See Commonwealth v. 
Moore, 480 Mass. 799, 813 & n.12 (2018).  In any case, as 
discussed infra, there was no prejudicial error here. 
13 
 
to the type of firearm that was used to kill Blake and injure 
Elliot.8  See Commonwealth v. Barbosa, 463 Mass. 116, 122 (2012) 
("A weapon that could have been used in the course of a crime is 
admissible, in the judge's discretion, even without direct proof 
that the particular weapon was in fact used in the commission of 
the crime"). 
However, the fact that Watt had a .38 caliber firearm on 
his person at the time of his arrest does not offer the same 
probative value, because the evidence established that the 
victims were shot with .40 caliber bullets.  "Where a weapon 
definitively could not have been used in the commission of the 
crime, we have generally cautioned against admission of evidence 
related to it."  Barbosa, 463 Mass. at 122.  Although this 
evidence demonstrated Watt's familiarity with and access to 
firearms, by and large we "have not . . . viewed the tenuous 
relevancy of evidence of a person's general acquaintance with 
weapons as outweighing the likelihood that such evidence will 
have an impact on the jury unfair to a defendant."  Commonwealth 
v. Toro, 395 Mass. 354, 358 (1985).  The admission of the 
testimony that Watt was in possession of a .38 caliber firearm 
at the time of his arrest was therefore error.  However, the 
error was not unduly prejudicial as the evidence was 
                     
8 Glock is a firearm manufacturer that makes a variety of 
semiautomatic pistols, including several .40 caliber models. 
14 
 
overshadowed by and insignificant compared to the evidence that 
Watt had access to the type of firearm that was used in the 
crime.  Compare Barbosa, supra at 127; Toro, supra at 358-359.  
The evidence of Watt's possession of the .38 firearm therefore 
did not create a substantial likelihood of a miscarriage of 
justice. 
iv.  Cellular telephone evidence.  At trial, the 
Commonwealth presented evidence of the contents of Watt's 
cellular telephone (cell phone), including contact information, 
text messages, and incoming and outgoing cell phone calls.  The 
defendants argue that this evidence was admitted in error and 
warrants reversal.  The Commonwealth concedes that the cell 
phone evidence should have been suppressed, but argues that the 
error was harmless.  We agree with the Commonwealth. 
 
As an initial matter, we note that in Commonwealth v. 
White, 475 Mass. 583, 588-590 (2016), this court held that a 
warrant application must sufficiently demonstrate a nexus 
between the crime alleged and the article to be searched.  Here, 
because the warrant application did not sufficiently demonstrate 
this nexus, the evidence obtained from Watt's cell phone should 
not have been admitted.9  Because Watt moved to suppress the 
                     
9 The decision in Commonwealth v. White, 475 Mass. 583 
(2016), was released after the trial in this case.  However, 
because the defendants' appeals still were pending, the 
standards set are applied retroactively.  See Commonwealth v. 
15 
 
contents of his cell phone, the admission of this evidence is 
preserved constitutional error and the burden is on the 
Commonwealth to show that the introduction of the evidence was 
harmless beyond a reasonable doubt.  See Commonwealth v. 
Charros, 443 Mass. 752, 765, cert. denied, 546 U.S. 870 (2005). 
 
In evaluating whether introduction of inadmissible evidence 
was harmless beyond a reasonable doubt, "we consider the 
importance of the evidence in the prosecution's case; the 
relationship between the evidence and the premise of the 
defense; who introduced the issue at trial; the frequency of the 
reference; whether the erroneously admitted evidence was merely 
cumulative of properly admitted evidence; the availability or 
effect of curative instructions; and the weight or quantum of 
evidence of guilt" (quotation and citation omitted).  
Commonwealth v. Monroe, 472 Mass. 461, 472-473 (2015).  Here, 
the cell phone evidence was cumulative of other evidence 
presented and posed little risk of prejudice to the defendants 
in light of the strength of the Commonwealth's case. 
 
First, the contact list extracted from the cell phone 
included "Yosimidy," the nickname for Mattis, as well as "RG" 
and "Tmack," both of whom had been identified as being 
associated with the Flatline gang.  Although this evidence was 
                     
Augustine, 467 Mass. 230, 257-258 (2014), S.C., 470 Mass. 837 
and 472 Mass. 448 (2015). 
16 
 
relevant to show Watt's connection with Mattis and other members 
of Flatline, multiple witnesses testified regarding the close 
relationship between Watt and Mattis, as well as Watt's 
association with Flatline.  Thus, the information from the 
contact list was cumulative.  See Commonwealth v. Hobbs, 482 
Mass. 538, 550-551 & n.14 (2019) (improperly admitted cell site 
location information evidence was harmless because it was not 
incriminating and there was ample other evidence of defendant's 
guilt); Perez, 411 Mass. at 260-261 (erroneous admission of 
defendant's inculpatory statements harmless where merely 
cumulative of properly admitted evidence). 
 
The Commonwealth also introduced evidence of a missed call 
from Watt to Mattis, followed by a text message to a friend 
stating, "Tell shedon [sic] to call me a.s.a.p its important 
please."  The Commonwealth argued in closing that the missed 
call and text message were evidence of the defendants' joint 
venture, close relationship, and consciousness of guilt.  
Although the admission of this evidence was error, there was no 
prejudice stemming from it given that there was nothing 
inherently incriminating about it.  See Commonwealth v. Broom, 
474 Mass. 486, 497-498 (2016). 
b.  Instruction on involuntary manslaughter.  The 
defendants argue that the judge erred by failing to provide an 
instruction on involuntary manslaughter.  They contend that, had 
17 
 
the jury been given the option to consider involuntary 
manslaughter, they would have been entitled to find either or 
both of the defendants guilty under that theory instead.  
Because neither defendant requested such an instruction, we 
consider whether the absence of the instruction resulted in a 
substantial likelihood of a miscarriage of justice.  We conclude 
it did not. 
 
"Involuntary manslaughter is an unlawful homicide 
unintentionally caused by an act which constitutes such a 
disregard of probable harmful consequences to another as to 
amount to wanton or reckless conduct" (quotation and citation 
omitted).  Commonwealth v. Carrillo, 483 Mass. 269, 275 (2019).  
"Wanton or reckless conduct is conduct that creates a high 
degree of likelihood that substantial harm will result to 
another."  Id., quoting Model Jury Instructions on Homicide 88 
(2018) (involuntary manslaughter).  See Commonwealth v. 
Welansky, 316 Mass. 383, 399 (1944).  Based on the evidence 
presented to the jury, Watt, the apparent shooter, intentionally 
shot multiple times at the two victims.  "Firing a [firearm] 
multiple times, directed toward specific individuals, provides a 
sufficient basis to conclude that the defendant understood the 
likely deadly consequences of his actions."  Commonwealth v. 
Pina, 481 Mass. 413, 424 (2019), quoting Commonwealth v. Braley, 
449 Mass. 316, 332 (2007).  On the facts of this case, no 
18 
 
reasonable jury could conclude that Watt was the shooter but 
that his conduct was simply wanton or reckless. 
 
Mattis, the coventurer, argues that he was entitled to an 
instruction on involuntary manslaughter because the jury could 
have concluded that he merely "recklessly" gave a firearm to 
Watt for self-protection, or to frighten the teen he 
encountered, but did not share Watt's intent to kill.  See 
Commonwealth v. Rakes, 478 Mass. 22, 32 (2017).  In support of 
this contention, he cites Commonwealth v. Tavares, 471 Mass. 
430, 441 (2015), where we emphasized that it is possible for two 
or more defendants to participate knowingly in a criminal act 
with different mental states with respect to that act.  We 
conclude that Mattis might have been entitled to receive an 
involuntary manslaughter instruction had he requested it, but 
that it was not error for the judge to fail to provide such an 
instruction where it was not requested and, in view of the 
evidence presented, the absence of the instruction did not 
result in a substantial likelihood of a miscarriage of justice. 
 
Just prior to the shooting, Mattis provided a firearm to 
Watt along with the instruction, "go handle that."10  That 
                     
 
10 The defendants argue that their trial counsel were 
ineffective in failing to challenge Rodriguez on his ability to 
overhear Mattis speaking to Watt from where Rodriguez was 
located.  As discussed infra, we disagree.  See part 2.b.  
However, that issue has no bearing on entitlement to an 
instruction on involuntary manslaughter. 
19 
 
evening, after the shooting, the two defendants celebrated 
together.  Given Mattis's conduct both before and after the 
shooting, it is extremely unlikely that a reasonable jury would 
have found that Mattis handed Watt the firearm solely for self-
protection or to frighten the teen; if he had, one would not 
expect him to be celebrating after the shooting.  See 
Commonwealth v. Dyous, 436 Mass. 719, 731-732 (2002) (defendant, 
whose coventurer shot into occupied motor vehicle, not entitled 
to involuntary manslaughter instruction as evidence "pointed 
singularly to an intent to kill," including bringing gun to 
victim's apartment complex and gloating immediately after 
murder). 
 
We also note that the defendants mounted a third-party 
culprit defense.  Because the defendants' theory of the case was 
that they were not involved in the shooting at all, neither 
defendant ever argued that the evidence only supported the 
finding that they now claim the jury could have found.  And 
making such an argument would have been inconsistent with the 
focus of this defense. 
 
For all these reasons, we conclude that the judge did not 
err in failing to provide an involuntary manslaughter 
instruction where it was not requested, and that its absence did 
not create a substantial likelihood of a miscarriage of justice. 
20 
 
c.  Constitutionality of sentences.  Both Watt and Mattis 
appeal from their mandatory sentences, contending that, due to 
their ages, seventeen and eighteen respectively, the sentences 
violate art. 26 of the Massachusetts Declaration of Rights and 
the Eighth Amendment to the United States Constitution. 
i.  Watt.  In Diatchenko v. District Attorney for the 
Suffolk Dist., 466 Mass. 655 (2013) (Diatchenko I), S.C., 471 
Mass. 12 (2015), we held that a sentence of life without the 
possibility of parole pursuant to G. L. c. 265, § 2, is 
unconstitutional as applied to juveniles, that is, those under 
the age of eighteen.  Id. at 658, 660.  See G. L. c. 265, § 2, 
as amended through St. 1982, c. 554, § 3.  In effect, our 
holding reduced the mandatory life sentence for juveniles 
convicted of murder in the first degree to the next-most severe 
sentence under the sentencing statute, a mandatory sentence of 
life with the possibility of parole after fifteen years, which 
was then the sentence for murder in the second degree.11  See 
Diatchenko I, supra at 672-673. 
                     
11 In 2014, after our decision in Diatchenko v. District 
Attorney for the Suffolk Dist., 466 Mass. 655 (2013) (Diatchenko 
I), S.C., 471 Mass. 12 (2015), the Legislature amended the 
sentencing statute to specify increased penalties for juveniles 
convicted of murder in the first degree.  See G. L. c. 279, 
§ 24 (b), as amended through St. 2014, c. 189, § 6; Commonwealth 
v. Okoro, 471 Mass. 51, 55 n.4 (2015).  Under the new sentencing 
scheme, a juvenile convicted of murder in the first degree based 
on extreme atrocity or cruelty is subject to a mandatory 
sentence of life imprisonment with the possibility of parole 
21 
 
Watt, who was seventeen at the time of the killing, was 
sentenced to life in prison with the possibility of parole after 
fifteen years.  He essentially maintains that a mandatory life 
sentence for juvenile homicide offenders, even with the 
possibility of parole, is unconstitutional and that instead he 
is entitled to an individualized sentencing hearing in which his 
juvenile status is considered.12 
We have considered and rejected identical claims in the 
past.  In Commonwealth v. Okoro, 471 Mass. 51 (2015), we 
rejected the defendant's claim that a mandatory sentence of 
imprisonment for life with parole eligibility after fifteen 
years is unconstitutional for a juvenile offender convicted of 
murder in the second degree.  Id. at 55-58.  Although we left 
open the question whether ongoing scientific and legal 
developments might cause us to reconsider our holding, see id. 
at 58, last year in Commonwealth v. Lugo, 482 Mass. 94 (2019), 
we reaffirmed Okoro's holding that "a mandatory life sentence 
                     
after thirty years.  See G. L. c. 279, § 24, second par.  
However, the defendants in this case were sentenced for first-
degree murder in 2013, when the sentencing statute, as limited 
by Diatchenko I, mandated a sentence of life with the 
possibility of parole after fifteen years.  See Diatchenko I, 
supra at 673. 
 
12 Watt's argument on this issue consisted of a statement 
that he "adopts the arguments of Mr. Lugo and amici," referring 
to the defendant in Commonwealth v. Lugo, 482 Mass. 94 (2019), a 
case that had yet to be decided when the defendants filed their 
brief. 
22 
 
with parole eligibility after fifteen years for a juvenile 
homicide offender . . . is constitutional."  Id. at 100, citing 
Okoro, supra at 60.  At that time, we were "unpersuaded that the 
law and science [had been] firmly established to warrant further 
consideration."  Lugo, supra.  As Watt advances no further 
reasons to revisit our recent holding, we conclude that his 
sentence is constitutional. 
ii.  Mattis.  Mattis, who turned eighteen years old 
approximately eight months before the shooting, received a 
mandatory sentence of life without the possibility of parole 
pursuant to G. L. c. 265, § 2.  He contends that such a sentence 
is unconstitutional for any individual under the age of twenty-
two.  We previously have acknowledged that, because juveniles 
have "diminished culpability and greater prospects for reform, 
. . . they do not deserve the most severe punishments" 
(quotations omitted).  Diatchenko I, 466 Mass. at 660, citing 
Miller v. Alabama, 567 U.S. 460, 471 (2012).13  We therefore 
concluded that a term of life without the possibility of parole 
for an individual under the age of eighteen violates the 
                     
13 In Miller v. Alabama, 567 U.S. 460, 470 (2012), the 
United States Supreme Court held that imposing a mandatory 
sentence of life in prison without the possibility of parole is 
a violation of the Eighth Amendment to the United States 
Constitution as applied to juveniles. 
23 
 
prohibition against cruel or unusual punishment contained in 
art. 26.  Diatchenko I, supra at 671. 
Mattis points to research that shows that the same 
developmental traits that exist for those under the age of 
eighteen apply to those between eighteen and twenty-two years 
old.  Thus, he argues, we should expand our holding in 
Diatchenko I so that, like those under the age of eighteen, 
homicide offenders between the ages of eighteen and twenty-two 
are eligible for parole after fifteen years.14 
In the six years since we decided Diatchenko I, we 
repeatedly have declined to extend its holding to individuals 
over eighteen years of age.  See Commonwealth v. Garcia, 482 
Mass. 408, 413 (2019); Commonwealth v. Colton, 477 Mass. 1, 18-
19 (2017); Commonwealth v. Chukwuezi, 475 Mass. 597, 610 (2016).  
However, we also repeatedly have acknowledged that "researchers 
continue to study the age range at which most individuals reach 
adult neurobiological maturity, with evidence that . . . 
[certain] brain functions are not likely to be fully matured 
                     
14 Alternatively, like Watt, Mattis argues for a sentencing 
hearing in which a judge is able to determine an appropriate 
sentence based on his particularized circumstances.  For the 
reasons discussed infra, we do not have sufficient information 
to determine whether G. L. c. 265, § 2, is unconstitutional as 
applied to those eighteen years of age and older; we likewise 
lack a sufficient basis to determine whether individuals older 
than eighteen years of age are entitled to an individualized 
sentencing hearing. 
24 
 
until around age twenty-two," and that such "research may relate 
to the constitutionality of sentences of life without parole for 
individuals other than juveniles."  Garcia, supra at 412-413, 
quoting Okoro, 471 Mass. at 60 n.14.  See Lugo, 482 Mass. at 
100. 
As research in this area has progressed since Diatchenko I 
was decided, it likely is time for us to revisit the boundary 
between defendants who are seventeen years old and thus shielded 
from the most severe sentence of life without the possibility of 
parole, and those who are eighteen years old and therefore 
exposed to it.  We can only do so, however, on an updated record 
reflecting the latest advances in scientific research on 
adolescent brain development and its impact on behavior.  See 
Diatchenko I, 466 Mass. at 669-670. 
Although we do not fault defense counsel, the record here 
is insufficient.  In Mattis's first motion for a new trial, he 
challenged the constitutionality of his sentence and requested 
an evidentiary hearing on the question.  He requested funds to 
retain an expert on brain development in teens and young 
adults.15  At the hearing on Mattis's first motion for a new 
trial, the Commonwealth opposed the request for evidence to be 
                     
 
15 Mattis further requested that the judge hold an 
evidentiary hearing on the question, and then "report it to the 
Supreme Judicial Court for resolution." 
25 
 
taken on the ground that the "already known science" would 
permit the defendant to make his argument."16  After the hearing, 
the judge denied the requests for an evidentiary hearing and 
expert funds.  Mattis again challenged the constitutionality of 
his sentence in his renewed motion for a new trial, this time 
submitting expert testimony and a related trial court order from 
a Kentucky case regarding the imposition of the death penalty on 
defendants younger than twenty-one years old.  The judge 
ultimately denied Mattis's renewed motion for a new trial. 
Because Mattis was prepared to present additional evidence 
on this issue, it would be manifestly unjust to reject Mattis's 
constitutional argument based on the insufficiency of the 
record.  Compare Commonwealth v. Epps, 474 Mass. 743, 767 (2016) 
("our touchstone must be to do justice," including where "a 
defendant was deprived of a substantial defense . . . [due to] 
the inability to make use of relevant new research findings").  
We therefore take this opportunity to remand this case to the 
Superior Court for development of the record with regard to 
research on brain development after the age of seventeen.  This 
will allow us to come to an informed decision as to the 
                     
 
16 On appeal, the Commonwealth appears to have switched 
gears, arguing that the available record is not sufficiently 
developed to provide a sufficient basis upon which to resolve 
the question. 
26 
 
constitutionality of sentencing young adults to life without the 
possibility of parole.17 
 
2.  Motions for a new trial.  The defendants also appeal 
from the denial of their motions for a new trial based on juror 
issues discovered posttrial as well as ineffective assistance of 
counsel. 
 
a.  Jury contamination.  The defendants argue that the 
judge improperly denied their motions for a new trial based on a 
tainted jury.  We conclude that there was no significant error 
of law or abuse of discretion in declining to grant the 
defendants a new trial on this basis.  See Commonwealth v. 
Grace, 397 Mass. 303, 307 (1986), and cases cited. 
After trial, Mattis's counsel became aware that a juror 
reported seeing Mattis "throwing gang signs" at the surviving 
                     
 
17 Mattis additionally argues on appeal that because he and 
Watt are only eight months apart in age, the disparity between 
their sentences violates equal protection guarantees because 
there is no principled reason to sentence Mattis to life without 
the possibility of parole and Watt, the shooter, to life with 
parole eligibility after fifteen years.  However, we have held 
on more than one occasion that "there is a rational basis for 
making determinations of parole eligibility based on age."  
Commonwealth v. Chukwuezi, 475 Mass. 597, 610 n.21 (2016).  See 
Commonwealth v. Wiggins, 477 Mass. 732, 748 (2017).  See also 
Roper v. Simmons, 543 U.S. 551, 574 (2005) (age of eighteen "is 
the point where society draws the line for many purposes between 
childhood and adulthood"). 
 
27 
 
victim during the victim's testimony.18  Thereafter, in response 
to a posttrial motion, the judge sent letters to each of the 
twelve deliberating jurors asking whether they had observed any 
hand gestures during the trial.  The judge conducted a voir dire 
of the two jurors who indicated that they observed the hand 
gestures.  Based on the jurors' testimony, the judge found that 
Mattis made gestures that both jurors believed to be "gang 
signs" directed at the victim,19 and that there was "tension 
between both defendants and the victim in the form of sustained 
mutual glaring."  The judge further found that there was "at 
least some discussion" of the gestures during jury deliberations 
"by at least these two jurors."20 
 
Based on the voir dire of the two jurors, the judge 
determined that the jury were not exposed to an extraneous 
influence, and that there was no showing that any juror harbored 
                     
18 After trial, the juror mentioned the incident to his 
neighbor, who was a friend of Mattis's trial counsel.  Appellate 
counsel for Mattis disclosed the juror's comments to the judge. 
 
19 The first juror questioned was a journalist who had 
written articles regarding gang-related problems in and around 
Boston.  He stated that he became familiar with gang symbols 
while working with police assigned to the gang unit.  The second 
juror stated that he recognized the gestures as being similar to 
those he had seen on television. 
 
 
20 When asked whether he spoke with any of the other jurors 
before or during the deliberations about the gestures, the 
second juror questioned stated that during deliberations he 
spoke with another juror who also saw the gestures. 
28 
 
racial animus.  She therefore denied the defendants' requests 
for a further inquiry of all jurors and denied their motions for 
a new trial.  We conclude that the judge neither abused her 
discretion nor erred in her handling of the posttrial claims of 
jury contamination.21 
 
i.  Extraneous influence.  The defendants contend on appeal 
that the "independent prior knowledge" upon which two jurors 
relied to conclude that the gestures they observed were gang-
related was extraneous information that tainted the verdicts.22  
See note 21, supra.  To succeed on such a claim, the defendants 
                     
21 In arguing that the judge failed to investigate 
thoroughly the impact of the hand gestures and failed to inquire 
whether racial bias may have affected the outcome of the trial, 
the defendants contend that the judge erred in light of 
Commonwealth v. Moore, 474 Mass. 541 (2016).  We disagree.  In 
addition to clarifying that, with certain exceptions, Mass. R. 
Prof. C. 3.5 (c), as appearing in 471 Mass. 1428 (2015), allows 
attorneys to speak to jurors without court authorization, in 
Moore, we made clear that "[n]othing in rule 3.5 (c) changes the 
standards governing requests for and the conduct of postverdict 
evidentiary hearings."  Moore, supra at 553.  In accordance with 
those standards, the judge here properly placed the initial 
burden on the defendants to demonstrate that the jury were 
exposed to an extraneous influence.  See Commonwealth v. Fidler, 
377 Mass. 192, 201 (1979).  Had the defendants met their burden, 
the Commonwealth would have been required to demonstrate that 
the defendants were not prejudiced by the extraneous influence. 
 
 
22 The defendants do not press here the argument made in 
their posttrial motions that the hand gestures themselves were 
the extraneous information.  We have long held that juries are 
"entitled to observe the demeanor of the defendant[s] during the 
trial."  Commonwealth v. Smith, 387 Mass. 900, 907 (1983).  See 
Commonwealth v. Houghton, 39 Mass. App. Ct. 94, 100 (1995) ("The 
demeanor of a witness in a courtroom has been considered 
evidence even if the witness does not take the stand"). 
29 
 
were required first to demonstrate that the jury were actually 
exposed to an extraneous matter.23  Commonwealth v. Fidler, 377 
Mass. 192, 201 (1979).  Here, after an evidentiary hearing, the 
judge concluded that neither the gestures nor any ensuing 
discussion about them constituted extraneous influences.  This 
determination was not an abuse of discretion.  See Commonwealth 
v. Bright, 463 Mass. 421, 441-443 (2012) (determination 
regarding existence of extraneous influence reviewed under abuse 
of discretion standard). 
 
The defendants' argument conflates extraneous information 
with the knowledge and experience that individuals bring with 
them when they sit as jurors.  "An extraneous matter is one that 
involves information not part of the evidence at trial 'and 
raises a serious question of possible prejudice.'"  Commonwealth 
v. Guisti, 434 Mass. 245, 251 (2001), quoting Commonwealth v. 
Kater, 432 Mass. 404, 414 (2000).  Examples include unauthorized 
views of the crime scene, improper communications with third 
parties, and consideration of documents or events not introduced 
in evidence.  See Fidler, 377 Mass. at 197 (collecting cases).  
See also Commonwealth v. Kincaid, 444 Mass. 381, 387 (2005) 
(jurors improperly considered fact of defendant's flight, which 
                     
 
23 Had the defendants met the threshold showing, the burden 
then would have shifted to the Commonwealth to show beyond a 
reasonable doubt that the defendants were not prejudiced by the 
extraneous matter.  Fidler, 377 Mass. at 201. 
30 
 
was not in evidence); Commonwealth v. Cuffie, 414 Mass. 632, 635 
(1993) (unauthorized visit to crime scene by juror).  Thus, 
extraneous information in this context refers to "specific facts 
not mentioned at trial concerning one of the parties or the 
matter in litigation."  Fidler, supra at 200. 
Here, the two jurors made observations of nonverbal 
interactions between the defendants and the victim in the court 
room during the victim's testimony.24  Each came to the same 
conclusion regarding the gestures they saw.  Whether the jurors 
were mistaken about the nature of the gestures will likely 
remain a mystery.  However, both applied their life experiences 
to understand what they saw, as they were instructed to do.  See 
Commonwealth v. Salazar, 481 Mass. 105, 117 (2018) ("It is well 
established that it is proper to ask a jury to rely on their 
common sense and life experience in assessing evidence and 
credibility"); Commonwealth v. Beal, 474 Mass. 341, 346 (2016) 
("Jurors are permitted to draw reasonable inferences from the 
evidence based on their common sense and life experience"). 
To expect jurors to perform their duties without the 
benefit of their life experiences is unrealistic and 
undesirable.  "We cannot expunge from jury deliberations the 
                     
24 As noted by the judge, in addition to the hand gestures 
made by Mattis, she found that both defendants and the victim 
engaged in "sustained mutual glaring" during the victim's 
testimony. 
31 
 
subjective opinions of jurors, their attitudinal expositions, or 
their philosophies."  Fidler, 377 Mass. at 199, quoting 
Government of the V.I. v. Gereau, 523 F.2d 140, 151 (3d Cir. 
1975), cert. denied, 424 U.S. 917 (1976).  See Commonwealth v. 
Williams, 481 Mass. 443, 451 (2019) ("It would neither be 
possible nor desirable to select a jury whose members did not 
bring their life experiences to the court room and to the jury 
deliberation room"). 
 
Because we conclude that no extraneous influences were 
injected into the jury deliberations, the judge did not err in 
denying the requests for further inquiry of all jurors and the 
motions for a new trial on that basis.25 
 
ii.  Alleged racial bias.  The defendants also argue that 
the judge erred in failing to inquire whether the jurors' 
interpretation of Mattis's gestures as gang signs (and thus 
                     
 
25 As neither the gestures themselves nor the "independent 
prior knowledge" that two jurors utilized to make sense of them 
were extraneous influences, the fact that the gestures were 
discussed amongst some jurors prior to and during deliberations 
is not a reason to question the validity of the verdict.  "With 
few exceptions, we adhere to the principle that 'it is essential 
to the freedom and independence of [jury] deliberations that 
their discussions in the jury room should be kept secret and 
inviolable.'"  Commonwealth v. Pytou Heang, 458 Mass. 827, 858 
(2011), quoting Fidler, 377 Mass. at 196.  See Commonwealth v. 
Mahoney, 406 Mass. 843, 856 (1990) ("any disregard by jurors of 
instructions from the judge not to discuss the case prior to 
deliberations would not provide a basis to conclude that the 
verdicts were tainted, in the absence of any concrete facts that 
the discussions involved matters not in evidence"). 
32 
 
indicia of gang membership) was the product of racial bias.  
"The presence of even one juror who is not impartial violates a 
defendant's right to trial by an impartial jury."  Commonwealth 
v. McCowen, 458 Mass. 461, 494 (2010), quoting Commonwealth v. 
Vann Long, 419 Mass. 798, 802 (1995).  However, the defendants 
failed to make any preliminary showing that racial bias was at 
play. 
 
To demonstrate that a postverdict juror inquiry regarding 
possible racial bias is warranted, a defendant bears the burden 
of proving by a preponderance of the evidence that a racially 
charged statement was made.  McCowen, 458 Mass. at 497.  See 
Pena-Rodriguez v. Colorado, 137 S. Ct. 855, 869 (2017) ("For the 
inquiry to proceed, there must be a showing that one or more 
jurors made statements exhibiting overt racial bias that cast 
serious doubt on the fairness and impartiality of the jury's 
deliberations and resulting verdict").  "If the defendant meets 
this burden, the burden then shifts to the Commonwealth to show 
beyond a reasonable doubt that the defendant was not prejudiced 
by the jury's exposure to [the] statements."  McCowen, supra.  
However, "[i]f the judge finds that the statements were not 
made, the judge need make no further findings."  Id. at 495. 
 
Here, although the defendants asked the judge to question 
each juror regarding potential racial bias, the defendants 
provided no proof, and in fact did not even allege, that any 
33 
 
juror made a statement or otherwise indicated that he or she 
harbored any racial animus at all.  The defendants' hypothesis 
that the verdicts were tainted by jurors who were not African-
American jurors, who interpreted "innocent gestures" by young 
African-American defendants as gang signs due to implicit or 
explicit bias, was not borne out by the judge's voir dire of the 
two jurors or by any other proof. 
 
Because the defendants have failed to meet their initial 
burden of demonstrating by a preponderance of evidence that the 
two jurors' observations had anything to do with racial bias, 
the judge did not err in denying the defendants' request to 
inquire about such bias.  See McCowen, 458 Mass. at 495. 
 
b.  Ineffective assistance of counsel.  The defendants' 
ineffective assistance of counsel claims center on the testimony 
of Rodriguez, a key witness for the Commonwealth.  At trial, 
Rodriguez testified that, prior to the shooting, he heard Mattis 
tell Watt, "[Watt] needed to go handle that," presumably 
referring to Elliott, whom Mattis had met at the convenience 
store.  This testimony contradicted Rodriguez's earlier 
statements to police and to the grand jury, where he testified 
that he did not hear either defendant say anything before the 
shooting.  Based on Rodriguez's testimony, the Commonwealth 
argued at closing that Mattis was guilty of joint venture murder 
34 
 
in the first degree because he specifically targeted the victims 
and directed Watt to shoot them. 
Posttrial, the defendants alleged in a supplemental claim 
in support of a motion for a new trial that it would have been 
impossible for Rodriguez to have heard Mattis's statements to 
Watt from Rodriguez's location, and that trial counsel were 
ineffective for failing to investigate Rodriguez's surprise 
testimony.26  The defendants supported this contention with an 
affidavit from a private investigator who averred that neither 
he nor his assistant could hear anything said by the other when 
standing in Rodriguez's and the defendants' purported positions.  
The defendants further requested funds to engage an acoustic 
expert to prove that Rodriguez's testimony that he heard Mattis 
speak to Watt was false.  The judge denied the request for funds 
and the motions for a new trial. 
 
On appeal, the defendants renew their claim of ineffective 
assistance of counsel.  To determine whether defense counsel was 
ineffective in defending a charge of murder in the first degree, 
we ask whether there was an error, and if so, whether the error 
"was likely to have influenced the jury's conclusion."  
                     
 
26 Rodriguez testified that the defendants were at the 
corner of Geneva and Levant Streets and that he was on the front 
porch of his home on Levant Street when he overheard Mattis.  
The record is silent as to the distance between those two 
points. 
35 
 
Commonwealth v. Wright, 411 Mass. 678, 682 (1992), S.C., 469 
Mass. 447 (2014) (substantial likelihood of miscarriage of 
justice standard).  See G. L. c. 278, § 33E.  If the claimed 
error relates to an attorney's strategic or tactical decision, 
the decision constitutes error "only if it was manifestly 
unreasonable when made" (citation omitted).  Commonwealth v. 
Coonan, 428 Mass. 823, 827 (1999). 
 
Without affidavits from trial counsel, we cannot say 
whether the alleged misstep was a strategic choice.  Either way, 
however, we conclude that the failure to investigate Rodriguez's 
physical ability to overhear Mattis did not amount to 
ineffective assistance on the part of either defendant's trial 
counsel. 
 
First, the defendants assert that, had counsel investigated 
this claim, they would have been able to prove conclusively that 
it would not have been possible for Rodriguez to have overheard 
Mattis.  In our view, however, the potential usefulness of an 
investigation is entirely speculative.  The defendants failed to 
explain how an acoustic expert would have been able to determine 
with any degree of certainty Rodriguez's physical ability to 
overhear Mattis, especially where the record does not indicate 
36 
 
the conditions under which Rodriguez allegedly heard Mattis's 
statements, including the volume of Mattis's voice.27 
 
We further note that the jury, who were taken on a view as 
part of the trial, had the opportunity to observe in person 
areas connected with the shooting, including the distance 
between Rodriguez's front porch and the corner of Geneva and 
Levant Streets.  They therefore were able to consider, and 
determine for themselves, the likelihood that Rodriguez 
physically was able to overhear the conversation.  Commonwealth 
v. Francis, 390 Mass. 89, 99 (1983) ("When the question whether 
expert testimony would aid the jury is close, the likelihood of 
prejudice from the admission or exclusion of that testimony is 
slight.  It is not surprising, therefore, that appellate courts 
have given great deference to the rulings of trial judges in 
this area of the law of evidence").  See Commonwealth v. 
Kingsbury, 378 Mass. 751, 753-754 (1979) (jurors permitted to 
rely on common sense in determining time of sunset in late 
October); Commonwealth v. Fitzgerald, 376 Mass. 402, 420 (1978) 
(jurors able to rely on view and common knowledge to determine 
that fear might exist in public housing projects). 
                     
 
27 The affidavits attached to the defendants' posttrial 
motion for expert funds similarly lacked details regarding the 
conditions under which the investigator performed his 
experiment.  For this reason, they are of questionable value. 
37 
 
 
In any case, even if information helpful to the defendants 
would have been uncovered had the matter been investigated, its 
use would have been limited to the impeachment of Rodriguez.  
Generally, failing to impeach a witness in a particular way does 
not constitute ineffective assistance.  See Commonwealth v. 
Jenkins, 458 Mass. 791, 805 (2011), citing Commonwealth v. Bart 
B., 424 Mass. 911, 916 (1997) ("Failure to impeach a witness 
does not, standing alone, amount to ineffective assistance").  
See also Commonwealth v. Hudson, 446 Mass. 709, 715 (2006), 
quoting Commonwealth v. Fisher, 433 Mass. 340, 357 (2001) ("it 
is speculative to conclude that a different approach to 
impeachment would likely have affected the jury's conclusion").  
Even on the more favorable standard of review under § 33E, a 
claim of ineffective assistance based on failure to use 
particular impeachment methods is difficult to establish.  
Hudson, supra, quoting Fisher, supra.  Contrast Commonwealth v. 
Haggerty, 400 Mass. 437, 441-442 (1987) (counsel's failure to 
investigate whether defendant's conduct proximately caused 
victim's injuries deprived defendant of only available defense 
and constituted ineffective assistance of counsel). 
 
Here, in a joint effort,28 the defense impeached Rodriguez 
vigorously with regard to his credibility.  On cross-
                     
 
28 Comparatively speaking, Mattis's counsel conducted a 
majority of the cross-examination of Rodriguez and devoted a 
38 
 
examination, counsel homed in on Rodriguez's inconsistent 
statements to the grand jury and investigators, and focused 
sharply on what he claimed to have seen and heard.  For example, 
counsel painstakingly walked Rodriguez through his statements to 
police and to the grand jury, and then his testimony on direct 
examination, regarding what Mattis wore the day of the shooting, 
demonstrating how Rodriguez's story changed for each audience.  
Counsel also directly questioned Rodriguez about his changing 
testimony regarding his ability to overhear Mattis and Watt's 
conversation, asking him to admit who he had lied to about his 
changing testimony. 
 
In addition to calling attention to Rodriguez's varying 
accounts of his observations of the defendants, trial counsel 
also effectively explored other avenues of impeachment, 
including Rodriguez's long history of auditory and visual 
hallucinations, his motive for testifying for the Commonwealth, 
and his demonstrated penchant for lying in other circumstances.  
During closing arguments defense counsel maintained that, given 
Rodriguez's extreme credibility issues, his testimony inherently 
was unreliable. 
In short, Rodriguez's shortcomings as a witness were 
thoroughly exposed, especially with regard to his credibility 
                     
larger share of her closing to raising doubts about his 
credibility. 
39 
 
and dishonesty.  Even assuming an investigation would have 
turned up additional impeachment material demonstrating that 
Rodriguez was untruthful, it would have been cumulative of the 
ample information trial counsel already had available and used 
effectively.  See, e.g., Commonwealth v. Vaughn, 471 Mass. 398, 
414 (2015) (failure to provide cumulative impeachment testimony 
not ineffective assistance). 
 
Because it is speculative to assume that an investigation 
would have yielded the result desired by the defendants, and any 
such result would have been limited to providing additional 
impeachment material regarding Rodriguez's credibility, an 
avenue thoroughly explored by the defense, we do not fault trial 
counsel for not pursuing (or considering) this strategy 
midtrial.29  See Commonwealth v. Satterfield, 373 Mass. 109, 115 
                     
 
29 Mattis argues that without Rodriguez's testimony that 
Mattis told Watt that Watt "needed to go handle that," the jury 
would have had insufficient evidence of joint venture murder in 
the first degree.  This argument is unavailing.  Evidence of 
Mattis's actions prior to the shooting, including his 
interaction with Elliott, his statements to both Rodriguez and 
Watt upon his return from his encounter with Elliott, and his 
handing a firearm to Watt, together with evidence of motive, 
consciousness of guilt, and "celebrating" after the shooting, 
provided sufficient evidence of joint venture murder even 
without Mattis's overheard statements to Watt just prior to the 
shooting. 
 
 
Mattis further argues that there was no evidence of intent 
with respect to the murder victim, Blake, because Blake was not 
present when Elliott told Mattis that Elliott was from Everton.  
To the contrary, there was evidence that Mattis was aware of, 
and intended harm to, both teenagers.  When Mattis returned from 
40 
 
(1977) ("in a case where ineffective assistance of counsel is 
charged, there ought to be some showing that better work might 
have accomplished something material for the defense").  We 
therefore conclude that counsel did not err and that, in any 
case, no substantial likelihood of a miscarriage of justice 
occurred. 
 
3.  Review under G. L. c. 278, § 33E.  The defendants 
contend that, as a result of all the aforementioned issues in 
combination, justice requires that they be granted a new trial 
under G. L. c. 278, § 33E.  For the reasons explained supra, we 
decline to exercise our extraordinary power to grant such relief 
pursuant to that statute. 
 
Conclusion.  For the foregoing reasons, the defendants' 
convictions and the orders denying their motions for a new trial 
and for postconviction relief are affirmed.  However, the matter 
of Mattis's sentence shall be remanded for an evidentiary 
hearing consistent with this opinion. 
 
 
 
 
 
 
 
So ordered. 
                     
the convenience store, he told Watt and Rodriguez, "[B]e easy, 
because that's them kids."  He then went on to provide Watt with 
a firearm and patted Watt on the shoulder prior to the shooting.  
Even if there was evidence that Mattis had the requisite intent 
only as to Elliott, "a defendant's intent . . . encompasses 
completely unintended victims (including victims of whom the 
defendant was unaware) who happen to suffer along with the 
intended victim."  Commonwealth v. Melton, 436 Mass. 291, 297-
298 (2002).