The Supreme Judicial Court (SJC) issued an opinion today requiring that juries be given comprehensive, detailed, cautionary instructions whenever the government calls an incarcerated informant as a witness, regardless of whether the informant is testifying pursuant to a cooperation deal. The Massachusetts high court also affirmed the general admissibility of defense expert testimony at trial “discussing the research regarding the unreliability of incarcerated informant testimony.” The SJC is following in the footsteps of Connecticut which has long required special cautionary jury instructions regarding informant testimony, and whose Supreme Court decided in State v. Leniart (2020) that defense expert testimony regarding informants is admissible. Here is a link to the SJC decision Commonwealth v. Lacrosse. Some excerpts from the SJC opinion:
We begin by acknowledging that the defendant raises legitimate concerns about the reliability of the testimony of incarcerated informants. . . . [W]e are persuaded that a more comprehensive and specific instruction directed at all incarcerated informant testimony, regardless of whether the incarcerated informant is testifying pursuant to a cooperation agreement, would be beneficial in future cases. . . .
Indeed, we have [] modified the Connecticut instruction to direct juries to consider how incarcerated informants may have accessed the information apart from a confession by the defendant, such as through access to the defendant’s discovery materials or media accounts of the crime.
Defense counsel may also, of course, present expert witness testimony discussing the research regarding the unreliability of incarcerated informant testimony so long as the requirements of Daubert-Lanigan are satisfied for such testimony. See State v. Leniart, 333 Conn. 88, 144 (2019) (expert testimony on “the general characteristics of the marketplace for criminal informant testimony and the academic research indicating that unreliable informant testimony contributes to many wrongful convictions” admissible so long as it satisfies other requirements for expert testimony).
For a more detailed explanation of why juries need expert help assessing jailhouse informants, see this explainer in The Appeal.