Jailhouse Informants in Massachusetts Criminal Cases: Reliability, the SJC’s New Jury Instruction, and Defense Strategies
In Massachusetts criminal trials, the Commonwealth can call many types of witnesses—police officers, bystanders, family members, alleged victims, and more. One of the most controversial categories is the incarcerated informant(also known as a jailhouse informant or jailhouse snitch). These witnesses claim that a defendant confessed or made incriminating statements while both were in custody in a Massachusetts jail or house of correction.
In 2024, the Massachusetts Supreme Judicial Court (SJC) addressed long-standing concerns about the reliability of this testimony in Commonwealth v. Lacrosse. The Court declined to require a special reliability hearing before such witnesses can testify in Massachusetts courts, but it did require a detailed, cautionary jury instruction in every Massachusetts criminal case involving an incarcerated informant—whether or not the informant has a formal cooperation agreement. This article explains what incarcerated informants are under Massachusetts law, why their testimony raises serious reliability issues, what the new Massachusetts jury instruction requires, and how an experienced Massachusetts criminal defense attorney challenges this evidence.
What Is an Incarcerated (Jailhouse) Informant in Massachusetts?
Under Massachusetts law, an incarcerated informant is a witness who was in custody at the time they offered to testify, or who is in custody when they actually testify, about a defendant’s alleged admissions or incriminating actions. The statements they describe may have occurred in a Massachusetts jail, house of correction, or elsewhere.
Typically, the informant claims the defendant made a direct confession (“I did it”) or more circumstantial admissions—such as talking about being at the crime scene, describing the weapon, or discussing how to hide evidence. In Massachusetts criminal prosecutions, these claims are then offered to prove identity, consciousness of guilt, or the defendant’s state of mind.
Why Is Jailhouse Informant Testimony Problematic in Massachusetts Courts?
Massachusetts courts have long recognized that incarcerated informants present unique reliability risks. Unlike ordinary civilian witnesses, these individuals often have powerful incentives to fabricate or exaggerate when testifying in a Massachusetts criminal trial.
Common motivations and risks include:
- Hope for favorable treatment: Reduced charges, lighter sentences, better housing, or other benefits in the informant’s own Massachusetts criminal case.
- Formal cooperation agreements: Written deals in which a Massachusetts district attorney’s office promises to consider the testimony when disposing of the informant’s charges.
- Fear or intimidation: Pressure from other inmates or a desire to appear cooperative with Massachusetts law enforcement.
- Revenge or personal bias: A grudge against the defendant.
- Access to case information: Informants may learn details from discovery materials provided in Massachusetts criminal cases, media coverage, or conversations with other inmates and then present those details as if they came from the defendant.
- Mental health or substance issues: Common among incarcerated populations in Massachusetts and capable of affecting perception and memory.
Because of these risks, wrongful-conviction research has repeatedly identified jailhouse informant testimony as a contributing factor in many overturned cases. In Massachusetts, judges act as gatekeepers for reliability while juries decide credibility. The tension between those roles is at the heart of the SJC’s decision in Commonwealth v. Lacrosse.
The Landmark Massachusetts Case: Commonwealth v. Lacrosse (2024)
In Commonwealth v. Lacrosse, a Massachusetts murder case, the defendant was charged with killing his former girlfriend. He did not deny the killing but raised an insanity defense under Massachusetts law, arguing he was not criminally responsible. At trial in Massachusetts Superior Court, the Commonwealth called two fellow inmates who claimed Lacrosse admitted the crime and said he planned to “play the crazy card.”
Defense counsel cross-examined both witnesses effectively—highlighting prior lies, memory problems, and a cooperation agreement. The jury nonetheless convicted. On appeal, the Massachusetts Supreme Judicial Court took the case. Lacrosse argued that the trial judge should have held a preliminary reliability hearing before allowing the informants to testify under Massachusetts evidence rules.
The SJC acknowledged the legitimate scientific and legal concerns about the unreliability of incarcerated informant testimony. However, it declined to require a special pretrial reliability hearing in Massachusetts. The Court concluded that Massachusetts juries, properly instructed, are capable of evaluating this evidence. Instead, the Massachusetts Supreme Judicial Court mandated a comprehensive jury instruction for all future Massachusetts criminal cases involving incarcerated informants—regardless of whether a formal cooperation agreement exists.
The Court also confirmed that Massachusetts defense counsel may present expert testimony on the general unreliability of incarcerated informant testimony, provided the expert evidence meets the Daubert-Lanigan standard applied in Massachusetts courts.
The Required Massachusetts Jury Instruction on Incarcerated Informants
Under the rule announced by the Massachusetts Supreme Judicial Court in Lacrosse, judges in Massachusetts criminal trials must now instruct juries that they should examine the testimony of an incarcerated informant with greater care and caution than ordinary witness testimony. The Massachusetts model jury instruction (adapted from Connecticut’s model and refined by the SJC) directs jurors to consider factors such as:
- The extent to which the informant’s testimony is confirmed by other evidence
- Whether the testimony contains details known only to the perpetrator
- Whether those details could have come from discovery materials in the Massachusetts case, media coverage, or other sources available to the informant
- Any benefits, promises, or inducements the informant has received or expects from Massachusetts prosecutors
- Whether the informant has testified as an informant in other cases
- Whether the informant has ever changed their story
The Massachusetts instruction also reminds the jury that the Commonwealth does not vouch for the truthfulness of the informant and that the ultimate question of credibility belongs solely to the jury. Jurors are not required to reject the testimony simply because the witness is an incarcerated informant, but they must scrutinize it carefully under Massachusetts law.
The Critical Role of a Massachusetts Criminal Defense Attorney
Even with the new Massachusetts jury instruction, the quality of the defense cross-examination remains decisive in Massachusetts criminal cases. An experienced Massachusetts criminal defense attorney will:
- Investigate the informant’s background: Prior Massachusetts convictions, history of cooperation with district attorneys, prior false statements, and any mental-health or substance issues.
- Obtain and scrutinize any cooperation agreement: What was promised by the Massachusetts prosecutor? What has already been delivered? What remains contingent?
- Probe alternative sources of information: Did the informant have access to the defendant’s discovery in the Massachusetts case? Local media accounts? Conversations with other inmates or correctional staff?
- Highlight inconsistencies and changes in the informant’s story: Over time, details often shift in ways that undermine credibility before a Massachusetts jury.
- Request the full cautionary Massachusetts jury instruction: And object if the judge’s charge is incomplete or watered down.
- Consider expert testimony: On the systemic problems with jailhouse informant evidence when the Massachusetts case and the science support it under Daubert-Lanigan.
Effective cross-examination by a skilled Massachusetts criminal defense lawyer can create reasonable doubt even when the Commonwealth presents an informant. The goal is to show the Massachusetts jury that the witness has strong reasons to lie and that the details they claim to know could easily have come from somewhere other than the defendant.
Practical Advice for Defendants in Massachusetts Custody
While every Massachusetts criminal case is different, experienced defense counsel routinely advise clients held in Massachusetts jails or houses of correction: do not discuss the facts of your case with anyone other than your lawyer; do not keep discovery materials in your cell if possible; and treat any inmate who seems overly interested in your case with extreme caution. Once information is shared in a Massachusetts facility, it can be difficult or impossible to control how it is later used against you.
Facing a Massachusetts Case Involving a Jailhouse Informant?
If the Commonwealth intends to call an incarcerated informant against you or a loved one in a Massachusetts criminal case, the quality of the defense response can determine the outcome. Contact Massachusetts Criminal Defense Attorney William J. Barabino for a confidential consultation. Call 781-393-5900 or visit www.williambarabino.com to discuss the evidence, the new Massachusetts jury-instruction requirements under Commonwealth v. Lacrosse, and the strategies available to challenge this type of testimony in Massachusetts courts.
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