Diaz v. City of Somerville, 59 F.4th 24

Background

Off-duty Somerville police officer Henry Diaz punched a pedestrian in East Boston (June 30, 2017); the pedestrian reported the incident but did not appear at criminal hearing and the case was dismissed without prejudice.
Somerville PD’s internal investigation (video, witness interviews, East Boston report) concluded Diaz was the aggressor and had lied during the investigation; the police chief recommended discipline up to dismissal.
A city hearing officer and the mayor found just cause and terminated Diaz; Diaz appealed to the Massachusetts Civil Service Commission, which after full hearings upheld the termination for misconduct and prevarication. Diaz did not seek judicial review of the Commission’s decision.
Diaz filed an MCAD charge and then sued the City alleging race discrimination under Mass. Gen. Laws ch. 151B and Title VII; the City moved for summary judgment in federal court.
The district court granted summary judgment: it held the unappealed Civil Service Commission decision precluded relitigation of disparate treatment for the chapter 151B claim, and that Diaz’s Title VII comparators were not sufficiently similar to show pretext. The First Circuit affirmed.

Issues

Issue	Plaintiff's Argument	Defendant's Argument	Held
Preclusive effect of unappealed Civil Service Commission decision on chapter 151B disparate-treatment claim	Diaz: Commission decided just cause, not discrimination; district court must adjudicate discrimination claim	City: Commission acted in adjudicatory capacity and decided materially identical issues; its unappealed decision has preclusive effect	Court held preclusion applies; Commission’s findings on comparators and just cause preclude relitigation under chapter 151B
Can Diaz rely on additional comparators presented at summary judgment to avoid issue preclusion	Diaz: new comparators not presented to Commission show disparate treatment	City: issue preclusion rests on prior opportunity to litigate, not on whether Diaz presented all possible evidence earlier	Court held prior full opportunity bars relitigation; new comparators do not defeat preclusion
Jurisdictional challenge: did filing an MCAD charge strip the Commission of authority to consider discrimination?	Diaz: MCAD filing gave MCAD exclusive jurisdiction over chapter 151B claims	City: issue was not raised before Commission or district court; therefore waived	Court held argument waived for failure to raise administratively and below
Sufficiency of comparators to show pretext for Title VII claim	Diaz: other officers who committed violent assaults (or lied) were treated more leniently, showing pretext	City: Diaz’s misconduct combined assault plus dishonesty; comparators lacked both elements and are not similarly situated	Court held comparators were not sufficiently similar (must match both violence and dishonesty); no evidence of pretext; summary judgment affirmed

Key Cases Cited

McDonnell Douglas Corp. v. Green, 411 U.S. 792 (1973) (established burden-shifting framework for discrimination claims)
Reeves v. Sanderson Plumbing Prods., Inc., 530 U.S. 133 (2000) (pretext may be shown by demonstrating employer's reason is unworthy of credence)
Univ. of Tenn. v. Elliott, 478 U.S. 788 (1986) (state administrative adjudications receive preclusive effect in federal court when state law so provides)
Bulwer v. Mount Auburn Hosp., 46 N.E.3d 24 (Mass. 2016) (Massachusetts modifies McDonnell Douglas; plaintiff need only show employer's stated reason is not the real reason)
Theidon v. Harvard Univ., 948 F.3d 477 (1st Cir. 2020) (discussing differences between federal and Massachusetts frameworks)
Dartmouth Rev. v. Dartmouth Coll., 889 F.2d 13 (1st Cir. 1989) (comparators must closely resemble plaintiff’s situation; apples-to-apples comparison)
Conward v. Cambridge Sch. Comm., 171 F.3d 12 (1st Cir. 1999) (reasonableness standard for similarly situated comparators)
Baez-Cruz v. Mun. of Comerio, 140 F.3d 24 (1st Cir. 1998) (preclusion principles for administrative factfinding)