Peterson v. Commonwealth, SJC 12281

Peterson was stopped for traffic infractions in a high‑gang area; he produced valid license and registration but officers ordered him out of the car and observed a knife clipped to his jeans.
Peterson was arrested for unlawful possession of a dangerous weapon (G. L. c. 269, § 10(b)), moved to suppress the knife as fruit of an unconstitutional exit order, and the motion was denied at trial.
A jury convicted Peterson; he was sentenced to 2½ years in a house of correction.
On direct appeal the Appeals Court reversed and set aside the verdict, holding the exit order lacked specific articulable facts supporting reasonable suspicion and therefore the knife should have been suppressed; the court did not reach Peterson’s sufficiency argument about whether the knife qualified as a dangerous weapon.
Peterson sued under the erroneous convictions statute, G. L. c. 258D, seeking compensation; the Superior Court denied the Commonwealth’s motion to dismiss, and the Commonwealth appealed to determine eligibility under § 1(B)(ii).
The Supreme Judicial Court held Peterson ineligible for relief because the Appeals Court reversed on constitutional (police conduct) grounds that do not "tend to establish" innocence under the statute.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether reversal on appellate suppression grounds satisfies G. L. c. 258D § 1(B)(ii) ("grounds which tend to establish innocence")	Peterson: reversal that led to dismissal of criminal charge makes him eligible; alternative claim that the knife was not a dangerous weapon (insufficient evidence) would also establish innocence	Commonwealth: reversal based on unconstitutional exit order concerns police conduct and deterrence, not probative of actual innocence; thus not eligible under § 1(B)(ii)	Court: Reversal based on unjustified exit order does not "tend to establish" innocence; Peterson is ineligible under § 1(B)(ii)
Whether arguments raised but not relied on by the Appeals Court (e.g., insufficiency of dangerous‑weapon element) can confer eligibility under § 1(B)(ii)	Peterson: his insufficiency claim was raised on appeal and could establish innocence if reached	Commonwealth: only grounds on which judicial relief was granted matter for eligibility; unadopted arguments do not qualify	Court: Arguments not relied upon by the court granting relief do not make a claimant eligible under § 1(B)(ii)

Guzman v. Commonwealth, 458 Mass. 354 (identifying that reversals must rest on facts probative of innocence to satisfy G. L. c. 258D eligibility)
Drumgold v. Commonwealth, 458 Mass. 367 (new trial order based on omissions that undermined key prosecution witnesses held to tend to establish innocence)
Irwin v. Commonwealth, 465 Mass. 834 (reversal for erroneous admission of consciousness‑of‑guilt evidence did not tend to establish innocence)
Renaud v. Commonwealth, 471 Mass. 315 (reversal for insufficient evidence on identity held to tend to establish innocence)
Ornelas v. United States, 517 U.S. 690 (noting exclusionary rule focuses on deterring unlawful police conduct, not establishing innocence)
Commonwealth v. Lora, 451 Mass. 425 (discussing suppression and exclusionary rule rationale)
Commonwealth v. Higgins, 85 Mass. App. Ct. 534 (explaining statutory requirements for a knife to qualify as a dangerous weapon under G. L. c. 269, § 10(b))