Commonwealth v. Thompson — Cell Tower Data and Consciousness-of-Guilt Evidence Satisfy G.L. c. 233, § 20I Corroboration Requirement for Immunized Accomplice Testimony

Case
Commonwealth v. John Thompson
Court
Massachusetts Appeals Court
Date Decided
2026-07-10
Docket No.
25-P-790
Judge(s)
Blake, C.J., Vuono & Neyman, JJ.
Topics
Criminal Law, Evidence, Accomplice Corroboration
Source
Full opinion on CourtListener · PDF

Background

On the evening of January 21, 2018, a masked intruder robbed an elderly Ayer resident at gunpoint, making off with prescription pills, cash, and the accomplice’s purse. Amanda McGadden had facilitated the robbery from the inside — scouting the home, confirming the victim was present, and ensuring the back door was unlocked — before John Thompson entered masked and armed. McGadden later testified against Thompson under a grant of immunity, recounting how Thompson recruited her, executed the robbery, and afterward drove to Leominster to spend the stolen money on pills. The victim’s roommate Arthur Osborne witnessed part of the robbery but could not identify the masked gunman. The victim himself named Thompson but was an unreliable witness whose account was riddled with delusions and inconsistencies.

A Superior Court jury convicted Thompson of home invasion under G. L. c. 265, § 18C, and masked armed robbery under G. L. c. 265, § 17. On appeal, Thompson raised two claims: (1) McGadden’s immunized testimony lacked the independent corroboration required by G. L. c. 233, § 20I, making the evidence legally insufficient; and (2) McGadden’s testimony that Thompson told her to describe the perpetrator as a “Black man” was so prejudicial that it created a substantial risk of a miscarriage of justice, even though defense counsel raised no objection at trial.

The Court’s Holding

Affirmed. The Massachusetts Appeals Court found neither claim persuasive.

Accomplice corroboration under G. L. c. 233, § 20I. Massachusetts’s corroboration statute — unique to this Commonwealth — bars conviction solely on the testimony of or evidence produced by an immunized witness. The court reiterated that corroborating evidence “need not connect the defendant to the crime, but must support at least one element of the crime.” Commonwealth v. Resende, 476 Mass. 141, 152 (2017). Here, four independent sources cleared that bar. First, Osborne’s testimony that McGadden — an acquaintance of both Thompson and the victim — was present and visible in the living room during the robbery corroborated her account of her own participation. Second, cell site location information placed Thompson’s phone in the corridors between Littleton, Concord, Ayer, and Leominster precisely when McGadden described each leg of the evening’s travel. Third, phone records documented eighteen text messages exchanged between Thompson’s and McGadden’s phones in the forty-five minutes surrounding the robbery, followed by a nearly five-minute call immediately after. Fourth, Thompson’s post-robbery conduct — denying to police that he knew McGadden, then providing a fabricated phone number for her — was evidence of consciousness of guilt. Commonwealth v. Martinez, 476 Mass. 186, 197 (2017). Taken together, the corroboration satisfied § 20I’s requirements.

Racial-direction testimony. McGadden testified that after the robbery Thompson told her, if officers asked about the perpetrator’s appearance, to “just say it was a [B]lack man.” Thompson argued for the first time on appeal that the statement had no probative value and served only to inflame the jury. Applying plain-error review under Commonwealth v. Randolph, 438 Mass. 290, 297 (2002), the court found no error warranting reversal. The statement was directly probative of Thompson’s consciousness of guilt — a calculated attempt to deflect police suspicion from himself. Commonwealth v. Vick, 454 Mass. 418, 424–426 (2009). While declining to condone racial bias, the panel concluded that on these facts the comment did not impermissibly suggest that Thompson harbored prejudice against Black men; its probative weight arose from the misdirection attempt, not from any character inference.

Key Takeaways

  • G. L. c. 233, § 20I — Massachusetts’s accomplice corroboration statute — bars conviction solely on immunized testimony, but the corroboration threshold is not demanding: it need only support at least one element of the crime. Cell site location data tracking the defendant’s movements consistent with the accomplice’s account, matching phone records, and an eyewitness placing the accomplice at the scene collectively satisfy the statute.
  • Consciousness-of-guilt evidence — lying to police about knowing a witness and furnishing a false phone number — can independently contribute to meeting the § 20I corroboration requirement.
  • Testimony that a defendant instructed an accomplice to lie by attributing the crime to someone of a particular race is probative of consciousness of guilt. On plain-error review, such testimony does not require reversal when its relevance lies in the defendant’s attempt to mislead police, not in any inference about the defendant’s racial attitudes.
  • Defense counsel who fail to object contemporaneously to testimony about a client’s racially charged statements invoke the “substantial risk of miscarriage of justice” standard on appeal — a significantly harder bar to clear than preserved-error review. In limine practice is critical when such evidence is foreseeable.

Why It Matters

For Massachusetts criminal practitioners, Thompson provides a workable illustration of how § 20I’s corroboration requirement operates with modern digital evidence. The statute has real teeth — Massachusetts is one of relatively few states requiring corroboration for immunized-witness testimony — but the case confirms that cell tower data, phone metadata, and a corroborating eyewitness’s presence account can collectively satisfy the statute even when the victim is an unreliable witness and the sole eyewitness could not make a visual identification. Defense lawyers challenging sufficiency in accomplice-immunity cases should carefully map each piece of corroborating evidence the prosecution will cite and focus attacks on gaps in the digital record or on the limited weight of consciousness-of-guilt inferences.

On the racial-direction issue, the panel’s holding turns on a narrow evidentiary characterization: the statement goes to consciousness of guilt, not to character. Practitioners defending against similar testimony should consider arguing in limine that the misdirection narrative can be conveyed without the racial specificity, and that the racial element introduces unfair prejudice that substantially outweighs its incremental probative value under Mass. G. Evid. § 403.

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