Title: Commonwealth v. Sullivan
Citation: N/A
Docket Number: SJC-11808
State: Massachusetts
Issuer: Massachusetts Supreme Court
Date: November 16, 2017

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SJC-11808 
 
COMMONWEALTH  vs.  GERALD SULLIVAN. 
 
 
 
Middlesex.     April 7, 2017. - November 16, 2017. 
 
Present:  Gants, C.J., Lenk, Gaziano, Budd, & Cypher, JJ. 
 
 
Homicide.  Felony-Murder Rule.  Armed Home Invasion.  
Deoxyribonucleic Acid.  Practice, Criminal, Witness, 
Hearsay, Confrontation of witnesses, Disclosure of 
evidence, Capital case.  Evidence, Hearsay, Expert opinion, 
Disclosure of evidence, Exculpatory, Qualification of 
expert witness, Impeachment of credibility.  Witness, 
Police officer, Expert, Impeachment, Competency, 
Credibility.  Constitutional Law, Confrontation of 
witnesses.  Due Process of Law, Disclosure of evidence. 
 
 
 
 
Indictments found and returned in the Superior Court 
Department on June 30, 2011.  
 
 
The cases were tried before S. Jane Haggerty, J., and a 
motion for a new trial, filed on September 9, 2015, was heard by 
Edward P. Leibensperger, J.  
 
 
 
Leslie W. O'Brien for the defendant. 
 
Jessica Langsam, Assistant District Attorney (Elizabeth A. 
Dunigan, Assistant District Attorney, also present) for the 
Commonwealth. 
 
 
 
 
2 
 
 
 
GAZIANO, J.  A Superior Court jury convicted the defendant 
of felony-murder, with the predicate felony of armed home 
invasion, in the shooting death of Johnny Hatch on 
February 18, 2011.1  In this direct appeal, the defendant argues 
that the evidence was insufficient to support his convictions.  
He also challenges several evidentiary rulings concerning the 
introduction of testimony about deoxyribonucleic acid (DNA) 
found on objects at the crime scene, and testimony concerning 
the use of a DNA profile of the defendant stored in the Combined 
DNA Index System (CODIS) database, which was described to the 
jury as a "national database."  In addition, the defendant 
maintains that the motion judge erred in denying his motion for 
a new trial on the ground that the Commonwealth did not provide 
exculpatory evidence concerning a forensic scientist's failure 
to pass required proficiency tests.  We conclude that the 
evidence was sufficient to support the convictions, and that 
none of the asserted errors in the trial proceedings requires a 
new trial.  Further, having carefully reviewed the record, 
pursuant to our duty under G. L. c. 278, § 33E, we discern no 
reason to exercise our extraordinary authority to grant a new 
trial or to reduce the verdict to a lesser degree of guilt.  
 
1.  Facts.  We recite the facts the jury could have found, 
                                                        
1 The defendant also was convicted of seven other related 
offenses.  See part 2, infra. 
3 
 
 
 
reserving certain facts for later discussion. 
 
At approximately 10 P.M. on February 18, 2011, John and 
Darlene Vieira2 were in their apartment in West Medford.  
Vieira's adult son, Johnny Hatch, was staying with them that 
night.  Hatch heard someone at the door and asked Vieira whether 
he was expecting anyone.  Although he was not expecting 
visitors, Vieira walked to the front door and asked who was 
there.  When he was unable to understand the response, he opened 
the door.  As soon as Vieira opened the door, two men dressed in 
black, wearing ski masks and gloves, attacked and overpowered 
him.  One said, "Where's the money and the jewelry?" or "We want 
your money and your jewelry."  One of the men was stocky and 
shorter than the other, approximately five feet, nine inches 
tall; the other was tall and thin. 
 
Vieira called to Hatch who ran into the living room, pulled 
the taller, thinner man away from Vieira, and fought with him, 
approximately seven or eight feet from where Vieira and the 
stocky man were struggling.  Hatch used a mallet and a length of 
metal pipe to hit the taller man on the head and shoulders.  
Vieira then heard a shot and saw his son lying on the floor.  
The taller man looked at Vieira, who was on his knees, and shot 
him in the head.  Vieira heard one of the men say, "They're 
                                                        
2 We refer to John Vieira by his last name; his wife, 
Darlene Vieira, was present in the apartment but had little 
involvement in the incidents at issue. 
4 
 
 
 
dead," and felt his body being rolled away from the door, before 
he lost consciousness. 
 
During the struggle, Darlene Vieira heard gunshots from her 
bedroom.  She telephoned 911 while hiding on the side of her 
bed.  Police arrived on the scene shortly after the gunshots 
were fired.  Officers found Vieira bleeding from the side of his 
head.  Vieira was transported to the hospital and recovered; 
Hatch was pronounced dead at the scene.  
 
On a Friday night in February, 2011,3 Sarah Rabbitt, a 
friend of the defendant, had planned to get together with the 
defendant and other friends, but had difficulty reaching him.  
When Rabbitt finally spoke with the defendant sometime between 
11:30 P.M. and midnight, she asked where he had been.  The 
defendant said that he had been at a friend's house.  Rabbitt 
noted that the defendant had a "little cut" and "some blood" on 
his head.  The defendant told her that he had been in a fight in 
East Boston. 
 
Investigating officers seized a number of items from the 
crime scene, including a mallet and a length of metal pipe, a 
mask, a black hat, a blue hat, and a jacket hood.  The 
investigation focused on individuals who might have had a 
connection to Vieira, who was known to investigators as a drug 
                                                        
3 Rabbitt testified that she saw the defendant on a Friday 
in February, but did not provide a specific date. 
5 
 
 
 
dealer, but they were unable to develop any leads.  
 
In March, 2011, a State police chemist conducted DNA 
testing of swabs taken from the black hat, the blue hat, the 
mallet head, and the length of pipe.  She uploaded the profiles 
into the CODIS database to search for a match.  The DNA on the 
black hat, the mallet, and the pipe matched the defendant's DNA 
profile.   
 
Based on these results, police obtained a buccal swab from 
the defendant, which was submitted to the State police crime 
laboratory for DNA testing.  A different State police chemist 
determined that the DNA on the mask matched the defendant's DNA, 
and that the defendant's DNA also matched the major profile from 
a mixed profile on the jacket hood; Hatch and Vieira were 
excluded from this profile.  The defendant's DNA profile 
generated from this swab also matched the major profile on the 
black hat and the profiles of the DNA on the mallet and the 
length of pipe.   
 
2.  Prior proceedings.  The defendant was arrested and 
indicted on charges of murder in the first degree, G. L. c. 265, 
§ 1; armed assault with intent to murder, G. L. c. 265, 
§ 18 (b); two counts of armed home invasion, G. L. c. 265, 
§ 18C; assault and battery by means of a dangerous weapon, G. L. 
c. 265, § 15A (c) (i); armed assault with intent to rob, G. L. 
c. 265, § 18 (b); carrying a firearm without a license, G. L. 
6 
 
 
 
c. 269, § 10 (a); and possession of a firearm without a firearm 
identification card, G. L. c. 269, § 10 (h).  On June 25, 2013, 
the jury returned guilty verdicts on all counts.4  The jury found 
the defendant guilty of felony-murder in the first degree, with 
the predicate felony of armed home invasion of the Vieira home.  
 
After the defendant filed his notice of appeal, the 
Commonwealth provided his counsel with a notice of postverdict 
discovery indicating that former State police crime laboratory 
criminalist Erik Koester had failed a number of proficiency 
tests.  Based on this, in October, 2015, the defendant filed a 
motion for a new trial and a motion for discovery.  In that 
motion, the defendant argued that evidence that Koester had 
failed the proficiency tests was relevant and exculpatory, and 
that this evidence would have been admissible as part of a 
Bowden defense.  See Commonwealth v. Bowden, 379 Mass. 472, 485-
486 (1980).  
 
We allowed the defendant's motion to stay the proceedings 
in this court so that he could pursue his motion for a new trial 
in the Superior Court.  A Superior Court judge (motion judge), 
who was not the trial judge,5 denied the defendant's motion for a 
new trial, and we consolidated the defendant's appeal from the 
                                                        
4 The Commonwealth dismissed the charge of armed assault 
with intent to rob, with respect to Hatch, before the jury began 
deliberations.  
 
5 The trial judge had retired.  
7 
 
 
 
denial of that motion with his direct appeal.  
 
3.  Discussion.  The defendant argues that the evidence was 
insufficient to support his convictions because the Commonwealth 
did not prove that he was armed when he entered the victims' 
apartment.  The defendant contends also that testimony that DNA 
taken from items found at the crime scene matched his DNA 
profile in the CODIS database was inadmissible hearsay and a 
violation of his right to confrontation.  The defendant further 
argues that the motion judge erred in denying his motion for a 
new trial on the ground that evidence of a State police 
criminalist's failure to meet proficiency standards was 
exculpatory under Brady v. Maryland, 373 U.S. 83, 87-88 (1963).   
 
a.  Sufficiency of the evidence.  In determining whether 
the record is sufficient to support a conviction, we consider 
"whether, after viewing the evidence in the light most favorable 
to the prosecution, any rational trier of fact could have found 
the essential elements of the crime beyond a reasonable doubt."  
Commonwealth v. Latimore, 378 Mass. 671, 677 (1979), quoting 
Jackson v. Virginia, 443 U.S. 307, 318-319 (1979).  
 
In order to prove that a defendant is guilty of felony-
murder in the first degree, the Commonwealth must prove beyond a 
reasonable doubt that the victim was killed during the 
defendant's commission or attempted commission of a felony with 
a maximum sentence of life imprisonment.  See Commonwealth v. 
8 
 
 
 
Scott, 408 Mass. 811, 821 n.10 (1990).  See also Commonwealth v.  
Brown, 477 Mass. 805, 807–808 (2017) (prospectively requiring 
actual malice for conviction of felony-murder).  "To find a 
defendant guilty of felony-murder, a jury are only required to 
find that the defendant intended to commit an underlying felony 
during which a death occurred."  Commonwealth v. Petetabella, 
459 Mass. 177, 191 (2011).  "[I]n the context of felony-murder, 
a defendant who uses a deadly weapon in the course of committing 
[a felony] will be held responsible for the injuries or deaths 
that occur as a consequence, regardless of his intent to inflict 
those consequences."  Id.   
To prove that the defendant committed the offense of armed 
home invasion, the Commonwealth was required to prove beyond a 
reasonable doubt that he (1) entered the dwelling of another, 
(2) knowing, or having reason to know, that one or more persons 
were present within the dwelling house when he entered or 
remained in it; (3) was armed with a dangerous weapon at the 
time of entry; and (4) used force or threatened the imminent use 
of force on any person within the dwelling house, or 
intentionally caused injury to any such person.  See 
Commonwealth v. Ruiz, 426 Mass. 391, 392-393 (1998) 
(Commonwealth must establish beyond reasonable doubt "that the 
defendant was armed with a dangerous weapon at the time of entry 
into a dwelling house").  
9 
 
 
 
 
Applying the familiar Latimore standard, we conclude that 
the Commonwealth presented sufficient evidence that the 
defendant was armed when he entered Vieira's apartment.  See 
Commonwealth v. Dung Van Tran, 463 Mass. 8, 24 (2012), citing 
Latimore, 378 Mass. at 677.  The Commonwealth established that 
two masked men entered the victims' apartment and attacked 
Vieira; Vieira struggled closely with the stocky man, and did 
not see or feel any weapons on him.  After Hatch grabbed the 
taller man and struck him in the head with a mallet and a metal 
pipe, the taller man shot Hatch and then shot Vieira in the 
head.   
 
Because the DNA on the pipe and the mallet matched the 
defendant's DNA, and because the defendant's friend noted a cut 
on his head at the relevant time period, the jury reasonably 
could have inferred that the defendant was the taller attacker 
who struggled with Hatch and fired the gun.  See Commonwealth v. 
Pytou Heang, 458 Mass. 827, 835-836 (2011) (evidence sufficient 
to support conviction of felony-murder where armed, masked 
intruders entered house, defendant was near scene shortly after 
crime, forensic evidence tied him to clothing found with murder 
weapon, defendant made statements to codefendant's girl friend 
regarding shooting, and defendant gave false statement to 
10 
 
 
 
police).6  
 
b.  CODIS database.  The defendant contends that a State 
police trooper's testimony that DNA collected from items found 
at the crime scene matched the defendant's DNA profile in the 
CODIS database constituted inadmissible hearsay, and that the 
judge's limiting instruction prejudiced him by highlighting that 
he previously might have been convicted of a crime.  The 
defendant maintains that the trooper's testimony violated his 
rights under the confrontation clause, given the absence of 
testimony from anyone "responsible for creating and maintaining" 
the database. 
 
After an extensive pretrial hearing, and a hearing at 
sidebar, the judge allowed the Commonwealth's motion in limine 
to admit the CODIS database evidence "to explain to the jury how 
the defendant became the focus [of the investigation]."  She 
permitted the officer who submitted the DNA evidence to testify 
only to the fact that the DNA evidence matched DNA from a 
                                                        
6 The Commonwealth also introduced evidence that Vieira did 
not have a gun and that he did not see Hatch with one.  See 
Commonwealth v. Platt, 440 Mass. 396, 401 (2003) ("A conviction 
may be based on circumstantial evidence alone, as long as that 
evidence is sufficient to find the defendant guilty beyond a 
reasonable doubt").  The defendant argues that the physical 
struggle between the intruders and the victims indicates that 
the intruders were not armed, because, had they been armed, no 
hand-to-hand struggle would have been necessary.  The defendant 
also argues that it was possible that Hatch was armed.  The jury 
apparently did not, and were not required to, draw these 
inferences. 
11 
 
 
 
"national database," and precluded the Commonwealth from 
eliciting evidence that the national database only contained DNA 
from criminal offenders or that the database is maintained by 
law enforcement solely for purposes of law enforcement.  The 
judge instructed the jury about the database at the time the 
trooper testified and in her final charge.  At the end of the 
trooper's testimony, the judge instructed,  
 
"I'd like to interrupt [the prosecutor] for a moment 
just to instruct the jury as to this particular topic.  
You've now heard evidence that [the defendant] was 
identified as a suspect in the investigation by matching 
unknown DNA that police obtained from items at the scene 
with a DNA profile of [the defendant] in a national 
database.  If you conclude that [the defendant's] DNA was 
in a database, a national database, you should not infer 
from that fact that the defendant committed the crimes 
alleged here or any other crime.  The national database 
contains DNA samples of many people for many different 
reasons and pursuant to individual [S]tate's laws.  You are 
not to speculate about what the reasons may have been in 
this case.  In particular, it would be incorrect for you to 
infer that, if you believed that [the defendant's] DNA was 
included in a national database, he must have committed 
some other crime in the past.  You should not assume that, 
conclude that, presume that.  That would be highly improper 
speculation and you must not engage in any such conjecture 
or speculation in this case."  
 
 
We conclude that there was no error in the judge's decision 
to allow evidence that investigators submitted crime scene DNA 
samples to "a national" DNA database.  The test results obtained 
from that database inquiry, however, should not have been 
admitted.  Nonetheless, in these circumstances, there was no 
prejudice to the defendant. 
12 
 
 
 
 
i.  Hearsay objection.  Because the defendant's objection 
to any reference to his DNA being in a database was preserved, 
we review to determine whether the introduction of the evidence 
was error, and if so, whether it was prejudicial.  See 
Commonwealth v. Cruz, 445 Mass. 589, 591 (2005).  See also 
Commonwealth v. Aviles, 461 Mass. 60, 66 (2011).  "An error is 
not prejudicial if it 'did not influence the jury, or had but 
very slight effect.'"  Cruz, supra, quoting Commonwealth v. 
Flebotte, 417 Mass. 348, 353 (1994). 
"We have permitted the use of carefully circumscribed 
extrajudicial statements in criminal trials to explain the state 
of police knowledge."  Commonwealth v. Rosario, 430 Mass. 505, 
508 (1999).  "[A]n arresting or investigating officer should not 
be put in the false position of seeming just to have happened 
upon the scene; he should be allowed some explanation of his 
presence and conduct."  Commonwealth v. Cohen, 412 Mass. 375, 
393 (1992), quoting McCormick, Evidence § 249, at 734 (E. Cleary 
ed., 3d ed. 1984).  Accordingly, there was no error in the 
judge's decision to allow introduction of the trooper's 
testimony that investigators submitted samples from DNA found on 
the pipe, the mallet, and the black hat to the CODIS database. 
 
Hearsay testimony to explain the reasons for police action, 
however, "carries a high probability of misuse, because a 
witness may relate 'historical aspects of the case, replete with 
13 
 
 
 
hearsay statements in the form of complaints and reports,' even 
when not necessary to show state of police knowledge."  Rosario, 
430 Mass. at 509, quoting McCormick, Evidence § 249, at 734.  
Accordingly, we have carefully circumscribed the use of such 
testimony, holding that it is admissible only if the testimony 
is based on the police officer's own knowledge, and is limited 
to the facts required to establish the officer's state of 
knowledge, and the police action or state of police knowledge is 
relevant to an issue in the case.  See Rosario, supra at 509-
510.  See, e.g., Commonwealth v. Perez, 27 Mass. App. Ct. 550, 
554–555 (1989), quoting McCormick, Evidence, supra ("The 
specific description of the defendant given to the investigator 
is . . . seldom needed and the likelihood of prejudice is great.  
For this reason a statement that an officer acted 'upon 
information received,' or 'as a consequence of a conversation,' 
or words to that effect -- without further detail -- satisfy the 
purpose of explaining police conduct").   
 
Here, evidence that the DNA profile was extracted from the 
pipe, mallet, and hat, and that that profile matched a national 
database of DNA for a particular person (i.e., the defendant) 
was improperly admitted hearsay because those responsible for 
conducting the CODIS database testing did not testify and were 
not subject to cross-examination.  Therefore, while the 
Commonwealth was permitted to offer testimony that a database 
14 
 
 
 
search was conducted, it was not permitted to offer testimony 
about the DNA match.  The facts presented to the jury were not 
limited to those needed to establish the state of police 
knowledge.   
 
We conclude, however, that the error was not prejudicial, 
because it "did not influence the jury, or had but very slight 
effect" (citation omitted).  Cruz, 445 Mass. at 591.  Apart from 
this testimony regarding the match to the defendant's DNA 
profile found using the database, State police crime laboratory 
chemists also testified to the match found using the defendant's 
DNA profile obtained from the buccal swab.  Therefore, evidence 
of a match was independently before the jury. 
 
Moreover, the jury instructions given contemporaneously 
with the testimony about the CODIS database, and in the judge's 
final charge, properly limited the jury's consideration of why 
the defendant's DNA was present in the database.  See 
Commonwealth v. Corliss, 470 Mass. 443, 452 (2015). 
 
ii.  Confrontation clause.  The defendant also contends 
that testimony about the CODIS database match constituted a 
violation of his rights to confrontation under the Sixth 
Amendment to the United States Constitution and art. 12 of the 
Massachusetts Declaration of Rights.  We agree.  Because the 
testimony involving the CODIS DNA match was testimonial hearsay 
admitted through a State police trooper without proper 
15 
 
 
 
foundation to establish personal knowledge, its admission 
violated the defendant's right of confrontation under the Sixth 
Amendment and art. 12.  While erroneous, we conclude that the 
improper admission of this evidence was harmless error. 
 
Under the Sixth Amendment and art. 12, a criminal defendant 
has the right to confront the government's witnesses.  See 
Bullcoming v. New Mexico, 564 U.S. 647, 658 (2011); Melendez-
Diaz v. Massachusetts, 557 U.S. 305, 329 (2009).  See also 
Commonwealth v. Nardi, 452 Mass. 379, 388 n.10 (2008) ("the 
protection provided by art. 12 is coextensive with the 
guarantees of the Sixth Amendment" [citation omitted]).  In 
addition, our common-law rules of evidence "afford a defendant 
more protection than the Sixth Amendment" (citation omitted). 
Commonwealth v. Tassone, 468 Mass. 391, 399 (2014).  Under the 
common law, we require that a defendant be provided with a 
"meaningful opportunity to cross-examine the expert about her 
opinion and the reliability of the facts or data that underlie 
her opinion."  Id.  In Tassone, we held that the "'primary 
purpose' of [a commercial laboratory] report in the instant case 
was to accuse the defendant and create evidence for use at 
trial," and that such an admission violated the defendant's 
rights under the confrontation clause (emphasis omitted).  Id. 
at 398, quoting Williams v. Illinois, 567 U.S. 50, 84 (2012). 
 
Because the erroneous admission of the CODIS testimony is a 
16 
 
 
 
preserved constitutional error, we consider whether the error 
was harmless beyond a reasonable doubt.  See Commonwealth v. 
Vasquez, 456 Mass. 350, 355 (2010).  Under this standard, we ask 
"whether there is a reasonable possibility that the evidence 
complained of might have contributed to the conviction."  
Commonwealth v. Perez, 411 Mass. 249, 260 (1991), quoting 
Chapman v. California, 386 U.S. 18, 24 (1967).  The following 
factors are relevant in making such a determination:  "(1) the 
relationship between the evidence and the premise of the 
defense; (2) who introduced the issue at trial; (3) the weight 
or quantum of evidence of guilt; (4) the frequency of the 
reference; and (5) the availability or effect of curative 
instructions."  Commonwealth v. Isabelle, 444 Mass. 416, 419 
(2005), quoting Commonwealth v. Mahdi, 388 Mass. 679, 696-697 
(1983).   
 
Here, the content of the CODIS database, and any notices 
provided to criminal investigators regarding that content, were 
inadmissible without testimony from those responsible for 
creating and maintaining the database.  The error nonetheless 
was harmless beyond a reasonable doubt, because the testimony 
was cumulative of other, properly admitted evidence that 
indicated a match between the DNA found on the items taken from 
the crime scene and the defendant's DNA profile.  See 
Commonwealth v. Bizanowicz, 459 Mass. 400, 409 (2011), quoting 
17 
 
 
 
Commonwealth v. Guy, 454 Mass. 440, 447 (2009) ("Although [the 
CODIS database] 'hit' focused attention on the defendant and led 
to the Commonwealth's obtaining a new sample of his DNA which 
then was sent to the . . . laboratory, it was the comparison by 
the . . . laboratory of his known DNA sample with the male DNA 
samples from the crime scene that led to the critical match used 
at trial").  The testimony regarding the CODIS DNA match 
therefore did not materially alter "the weight or quantum of 
evidence of guilt" presented to the jury (citation omitted).  
Isabelle, 444 Mass. at 419.  Further, with respect to "the 
relationship between the evidence and the premise of the 
defense," the defendant did not dispute the DNA match, and 
admitted to having been present in the Vieiras' apartment at the 
time of the events in question.7   
 
In short, the Commonwealth is permitted to introduce 
evidence that an investigator submitted crime scene DNA samples 
to a national database.  This testimony is admissible for the 
limited purpose of explaining the state of police knowledge.  
Upon its admission in evidence, the trial judge is required to 
provide the jury with a limiting instruction (like the 
                                                        
7 The defendant testified that he entered Vieira's apartment 
to purchase drugs, and was pushed from behind by an unknown man 
who attacked the occupants.  The assailant struck him on the 
head, and fired three shots at the occupants.  During the 
struggle, he lost his black hat and a face protector he wore for 
outdoor work and kept in his pocket. 
18 
 
 
 
instruction in this case) to minimize the prejudice to the 
defendant.  An investigator, however, may not testify that the 
crime scene DNA sample matched the defendant's DNA profile 
stored in the national database.  
 
c.  Nondisclosure of exculpatory evidence.  Finally, the 
defendant contends that the motion judge erred in denying his 
motion for a new trial because the evidence was exculpatory and 
he was prejudiced by his inability to challenge the 
criminalist's qualifications or to use the evidence to bolster a 
Bowden defense.  We conclude that there was no abuse of 
discretion in denying the defendant's motion for a new trial.  
Although evidence of the criminalist's failure to pass 
proficiency tests was, contrary to the motion judge's ruling, 
both exculpatory and admissible, its nondisclosure was not 
sufficiently prejudicial to warrant a new trial. 
 
Approximately two years after the defendant's trial, the 
prosecutor notified the defendant's appellate counsel that State 
police criminalist Erik Koester had failed several proficiency 
tests in trace evidence collection and blood spatter analysis.  
The State police crime laboratory informed Koester of the 
results in April, 2012, and immediately took corrective action 
against him.  Classified as committing Level I 
"nonconformities," which raised "immediate and validated concern 
regarding the quality of work produced," Koester was removed 
19 
 
 
 
from certain duties, and his prior casework was examined for 
possible errors. 
 
In denying the defendant's motion for a new trial, the 
motion judge found that the evidence was not exculpatory and was 
inadmissible to impeach Koester as unrelated misconduct, 
pursuant to Mass. G. Evid. § 404(b) (2017).  He also found that 
the defendant failed to establish that this evidence would have 
affected the jury's verdicts, given that Koester's involvement 
in the investigation was limited, and the defendant already had 
suggested at trial that Koester's work was not thorough.  
In reviewing the denial of a motion for a new trial, we 
"examine the motion judge's conclusion only to determine whether 
there has been a significant error of law or other abuse of 
discretion."  Commonwealth v. Grace, 397 Mass. 303, 307 (1986).  
"Judges are to apply the standard set out in Mass. R. Crim. 
P. 30 (b)[, as appearing in 435 Mass. 1501 (2001),] rigorously 
and grant such a motion only if it appears that justice may not 
have been done" (quotations and citation omitted).  Commonwealth 
v. DiCicco, 470 Mass. 720, 728 (2015).  Where, as here, the 
motion judge was not the trial judge, and where there was no 
evidentiary hearing, we are in "as good a position as the motion 
judge to assess the trial record" (citation omitted).  
Commonwealth v. Phinney, 446 Mass. 155, 158 (2006), S.C., 448 
Mass. 621 (2007).  
20 
 
 
 
 
In Brady v. Maryland, 373 U.S. at 87, the United States 
Supreme Court concluded that the government is constitutionally 
obligated to disclose material, exculpatory evidence for which a 
defendant has made a specific request.  In United States v. 
Agurs, 427 U.S. 97, 107 (1976), this obligation was extended to 
material, exculpatory evidence for which the defendant has made 
only general requests, or even no request.  To obtain a new 
trial on the basis of nondisclosed exculpatory evidence, a 
defendant must establish (1) that "the evidence [was] in the 
possession, custody, or control of the prosecutor or a person 
subject to the prosecutor's control"; (2) "that the evidence is 
exculpatory"; and (3) "prejudice."  Commonwealth v. Murray, 461 
Mass. 10, 19, 21 (2011).  See Strickler v. Greene, 527 U.S. 263, 
281-282 (1999) (evidence is favorable to accused if it is either 
exculpatory or impeaching).  
 
i.  Possession by the prosecution team.  As the motion 
judge found, Koester was a member of the prosecution team and 
was aware when he testified that he had failed his proficiency 
tests.  See Commonwealth v. Martin, 427 Mass. 816, 823-824 
(1998) (prosecution's duty to disclose exculpatory evidence to 
defense extended to evidence in possession of chemist at State 
police crime laboratory who "has participated in the 
investigation or evaluation of the case and has reported to the 
prosecutor's office concerning the case").  
21 
 
 
 
 
ii.  Exculpatory nature of evidence.  "The Brady obligation 
comprehends evidence which provides some significant aid to the 
defendant's case, whether it furnishes corroboration of the 
defendant's story, calls into question a material, although not 
indispensable, element of the prosecution's version of the 
events, or challenges the credibility of a key prosecution 
witness."  Commonwealth v. Ellison, 376 Mass. 1, 22 (1978).  
"Evidence may be favorable or exculpatory, and thus required to 
be disclosed, although it is not absolutely destructive of the 
Commonwealth's case or highly demonstrative of the defendant's 
innocence" (quotations and citation omitted).  Commonwealth v. 
Laguer, 448 Mass. 585, 595 (2007).  Rather, "exculpatory" in 
this context comprehends all evidence that tends to "negate the 
guilt of the accused" or support the accused's innocence 
(citation omitted).  Id.  
 
We agree, as the defendant argues, that this evidence was 
exculpatory.  See id.  "'[E]xculpatory . . . . is not a narrow 
term connoting alibi or other complete proof of innocence 
. . . ."  Commonwealth v. Healy, 438 Mass. 672, 679 (2003), 
quoting Ellison, 376 Mass. at 22 n.9.  This evidence falls under 
Brady; it could have been used to question Koester's competence 
as an expert witness, and to bolster the defendant's Bowden 
defense that the investigation was generally inadequate.  See 
Bowden, 379 Mass. at 485-486. 
22 
 
 
 
 
We do not agree with the motion judge that admission of 
this evidence was barred by Mass. G. Evid. § 404(b)(1) for use 
by the defendant to contradict or discredit Koester on cross-
examination.  Section 404(b) provides that "[e]vidence of a 
crime, wrong, or other act is not admissible to prove a person's 
character in order to show that on a particular occasion the 
person acted in accordance with the character."  "It is well 
established that impeachment by prior misconduct is not 
permissible."  Commonwealth v. Andrews, 403 Mass. 441, 459 
(1988).  See Commonwealth v. Sleeper, 435 Mass. 581, 605-607 
(2002) (applying rule of evidence to prior misconduct of expert 
witness). 
The defendant, however, does not seek to impeach Koester 
for prior misconduct per se, but, rather, for misleading the 
jury.  Koester testified to his qualifications and described the 
"extensive" training and the rigorous testing he was required to 
pass to attain his position at the laboratory.  He described his 
duties as including the examination of "trace evidence."  He did 
not mention his failure to pass a proficiency test in trace 
evidence collection, or his other deficient testing results.  
Evidence tending to impeach an expert witness for 
incompetence or lack of reliability falls within the ambit of 
the Commonwealth's obligations under Brady.  "The evidence [to 
be disclosed] must be favorable to the accused, either because 
23 
 
 
 
it is exculpatory, or because it is impeaching . . . ."  
Strickler, 527 U.S. at 281-282.  See United States v. Bagley, 
473 U.S. 667, 676 (1985) (both exculpatory and impeachment 
evidence may be favorable to accused under Brady standard).  In 
Murray, 461 Mass. at 20, we held that the evidence at issue was 
potentially exculpatory because it could be used to impeach a 
witness by contradiction and for bias. 
 
To a lesser extent, this evidence also was exculpatory 
because it bolstered the defendant's Bowden defense.  See 
Bowden, 379 Mass. at 486 ("The fact that certain tests were not 
conducted or certain police procedures not followed could raise 
a reasonable doubt as to the defendant's guilt in the minds of 
the jurors").  "[E]xculpatory evidence includes evidence whose 
value allows a defendant to attack the thoroughness and good 
faith of an investigation, . . . typically in cases where the 
suppressed evidence is needed to impeach a government witness."  
Pham vs. Terhune, U.S. Dist. Ct., No. C 02-1348 PJH (N.D. Cal. 
Mar. 20, 2008).  See United States v. Howell, 231 F.3d 615, 625 
(9th Cir. 2000), cert. denied, 534 U.S. 831 (2001) (factual 
errors in police reports were exculpatory, requiring disclosure 
under Brady; errors raised opportunity for defendant to attack 
thoroughness and good faith of investigation, and mistakes 
constituted "textbook examples" of impeachment evidence).  
 
iii.  Whether the nondisclosure was prejudicial.  We turn 
24 
 
 
 
to whether the nondisclosure of this evidence was so prejudicial 
as to warrant a new trial.  The motion judge concluded that, as 
the defendant had presented no evidence that he had made any 
specific request for information concerning Koester's 
proficiency tests, the standard of prejudice is "the same 
standard used to assess the impact of newly discovered evidence, 
that is, 'whether there is a substantial risk that the jury 
would have reached a different conclusion if the evidence had 
been admitted at trial."  Murray, 461 Mass. at 21, quoting 
Commonwealth. v. Tucceri, 412 Mass. 401, 413 (1992).  To be 
granted a new trial, a defendant must establish that there is a 
reasonable possibility that the evidence would have made a 
difference in the jury's verdicts.  See Laguer, 448 Mass. at 
594.  If the nondisclosed evidence, "in an over-all assessment, 
. . . does not carry a measure of strength in support of the 
defendant, the failure to disclose that evidence does not 
warrant the granting of a new trial."  Tucceri, supra at 414. 
 
In the circumstances here, the nondisclosure of Koester's 
failure to pass the proficiency tests did not rise to the 
requisite level of prejudice.  Koester's involvement in the 
investigation of the defendant was limited; he collected 
evidence, tested items for the presence of human blood, and sent 
the samples along to the DNA laboratory.  He was not directly 
responsible for the DNA testing that implicated the defendant in 
25 
 
 
 
the crimes.  As the motion judge found,   
 
"[Koester] collected certain objects and impressions 
at the crime scene and later tested them for traces of 
human blood.  His work did not directly match [the] 
defendant to those items -- other [State police] laboratory 
chemists did that through DNA analysis.  His investigation 
did not link [the] defendant to the scene of the crimes --- 
[the] defendant's own testimony did that by his admission 
that he was present during the crimes and was involved in 
physical altercations at the Vieiras' apartment.  The 
extent, not the fact, of [the] defendant's involvement in 
the events of February 18, 2011, was the central issue at 
trial.  Koester's work neither proves nor disproves that 
issue."  
 
The judge also noted that Koester's work had been reviewed by 
State police administration to determine if reexamination of 
evidence was required, and corrected reports would be issued 
where inaccurate information was noted; no corrected reports had 
been issued for this case.  
 
Moreover, while the evidence of Koester's test failures was 
admissible and exculpatory, it would not have made a difference 
in the jury's thinking or verdicts.  The actual DNA testing, in 
which Koester had no direct role, likely did the most damage to 
the defendant's case.  We held in Sleeper, 435 Mass. at 607, 
that an expert witness's misrepresentation of his credentials 
does not typically create a "substantial risk that the jury 
would have reached a different conclusion" (citation omitted).  
"Newly discovered evidence that tends merely to impeach the 
credibility of a witness will not ordinarily be the basis of a 
new trial."  Commonwealth v. Lo, 428 Mass. 45, 53 (1998), 
26 
 
 
 
quoting Commonwealth v. Ramirez, 416 Mass. 41, 47 (1993). 
 
In addition, the nondisclosure of evidence of Koester's 
failed proficiency testing did not preclude the defendant from 
raising a Bowden argument.  We agree with the motion judge's 
observation that the defendant "was able to make his general 
point to the jury without the evidence of nonconformities."  
Defense counsel questioned the competence of Koester's crime 
scene investigation by pointing out that he failed to find 
certain key items of evidence during his search of the 
apartment.  See Commonwealth v. Elangwe, 85 Mass. App. Ct. 189, 
196 (2014) ("Even if the impeachment of [witnesses] at trial on 
the bias at issue was not as effective or potent as it might 
have been [had the exculpatory evidence been offered at trial], 
that purpose was in fact accomplished" where jury were generally 
aware of witnesses' bias).  
 
The facts here are not akin to those in Martin, 427 Mass. 
at 817, where we affirmed the allowance of a motion for a new 
trial because the nondisclosed evidence concerned the testing of 
lysergic acid diethylamide (LSD), the drug compound that caused 
the victim's death.  The nondisclosed evidence here concerns an 
analyst's failings not directly related to the crimes at issue.  
Contrast Murray, 461 Mass. at 22-23 (affidavit of police officer 
who investigated street gang to which victim belonged where 
statements in affidavit contradicted testimony of gang-member 
27 
 
 
 
witnesses at trial); Commonwealth v. Gallarelli, 399 Mass. 17, 
22–24 (1987) (laboratory report confirming absence of blood on 
knife seized from defendant arrested for stabbing); Commonwealth 
v. Bennett, 43 Mass. App. Ct. 154, 158–163 (1997) (evidence 
showing defendant could not have made telephone calls to victim 
because defendant was detained in correctional facility); 
Commonwealth v. Vaughn, 32 Mass. App. Ct. 435, 439–440 (1992) 
(information that detective would testify to seeing three sets 
of footprints at the crime scene, when detective initially 
reported that there were two sets of footprints).  
 
d.  Review pursuant to G. L. c. 278, § 33E.  The defendant 
asks that we exercise our extraordinary power pursuant to G. L. 
c. 278, § 33E, and order a new trial or reduce his murder 
conviction to murder in the second degree.  After carefully 
reviewing the record pursuant to our duty under G. L. c. 278, 
§ 33E, we conclude that none of the asserted errors, standing 
alone or cumulatively, requires a new trial, and that there is 
no other basis on which to disturb the jury's verdicts.  
 
 
 
 
 
 
 
Judgments affirmed. 
 
Order denying motion for a              
new trial affirmed.