Mistrials in Massachusetts Criminal Cases

A mistrial ends a criminal trial before a verdict. The trial that was under way stops, the jury is discharged, and nothing that happened at that trial produces a conviction or an acquittal. What happens next depends on a question that sounds procedural and is not. It matters enormously who ended the trial and whether the defendant objected.

Where the defendant asked for the mistrial, or agreed to it, or had the chance to object and stayed silent, the Commonwealth is ordinarily free to try the case again. Where the judge ended the trial over the defendant’s objection, a second trial is barred unless the record shows a manifest necessity for stopping the first one. That distinction decides cases, and it is often settled in the few minutes a judge spends announcing a decision.

The Standard for Ending a Trial Without a Verdict

Jeopardy attaches when the jury is sworn. From that moment the defendant holds what the Supreme Court has called the valued right to have the trial completed by a particular tribunal. Wade v. Hunter, 336 U.S. 684, 689 (1949).

The governing rule is nearly two centuries old. A court may discharge a jury without a verdict where, taking all the circumstances into consideration, there is a manifest necessity for doing so, or the ends of public justice would otherwise be defeated. United States v. Perez, 22 U.S. (9 Wheat.) 579, 580 (1824), quoted in Commonwealth v. Cassidy, 410 Mass. 174, 177 (1991). The Supreme Court restated the standard in Arizona v. Washington, 434 U.S. 497, 505 (1978), and Massachusetts follows it.

State and federal double jeopardy protections bar, as a general rule, the retrial of a defendant whose first trial ended over his objection and without a conviction. The manifest necessity exception is what permits a second trial. Ray v. Commonwealth, 463 Mass. 1, 3 (2012); Commonwealth v. Steward, 396 Mass. 76, 78 to 79 (1985).

There are degrees of necessity. Arizona v. Washington, 434 U.S. 497, 506 (1978). Before declaring a mistrial over objection, the judge must hear from the defendant and consider the alternatives. Commonwealth v. Steward, 396 Mass. 76, 79 (1985).

The Appeals Court has put the caution in plain terms. A mistrial ought to be declared with the greatest caution, under urgent circumstances, and for very plain and obvious causes. Commonwealth v. Riberio, 49 Mass. App. Ct. 7, 11 (2000), quoting Commonwealth v. Horrigan, 41 Mass. App. Ct. 337, 340 (1996).

Within those limits the decision belongs to the trial judge. Commonwealth v. Cohen, 412 Mass. 375, 383 (1992); Commonwealth v. Cunneen, 389 Mass. 216, 223 to 224 (1983). A reviewing court will not disturb it absent an abuse of discretion.

Who Ends the Trial

Three actors can produce a mistrial, and the consequences differ.

The judge acting on the court’s own motion. Where the defendant objects, manifest necessity is required, and the failure to meet that standard bars a retrial.

The defendant moving for a mistrial. A defendant who successfully moves for a mistrial ordinarily gives up the double jeopardy objection to a second trial. Oregon v. Kennedy, 456 U.S. 667, 679 (1982); Mercedes v. Commonwealth, 405 Mass. 693, 696 (1989); Commonwealth v. Babb, 389 Mass. 275, 282 (1983).

The Commonwealth asking. A prosecutor’s request waives nothing on the defendant’s side. If the defendant objects and the judge grants it anyway, manifest necessity is still required.

Consent, Silence, and the Objection That Was Never Made

This is where the double jeopardy claim is most often lost, and it is lost quietly.

A defendant may consent to a mistrial explicitly, by moving for one or by agreeing to one proposed by the prosecutor or the judge, or implicitly, where the defendant had the opportunity to object and failed to do so. Commonwealth v. Edwards, 491 Mass. 1, 13 (2022).

Consent may be inferred from silence. Pellegrine v. Commonwealth, 446 Mass. 1004, 1005 (2006), quoting Commonwealth v. Phetsaya, 40 Mass. App. Ct. 293, 298 (1996). In Pellegrine the Supreme Judicial Court found consent where defense counsel assented without speaking, and having found consent the court did not reach the manifest necessity question at all.

An objection also has to be made to the mistrial that is being declared. Consent is not inferred from a mistrial motion the defendant made at an earlier stage of the trial, and neither does that earlier motion preserve an objection to a later mistrial. Jones v. Commonwealth, 379 Mass. 607, 621 (1980).

The practical rule for counsel is short. If the defendant wants the trial to continue, the objection must be stated on the record, at the time, in terms that identify the alternatives the judge should consider instead.

The Grounds for a Mistrial

A Deadlocked Jury

A jury that genuinely cannot agree is the strongest ground there is. The Supreme Judicial Court has called it the prototypical example of manifest necessity. Commonwealth v. Ellis, 432 Mass. 746, 751 (2000), quoting Commonwealth v. Andrews, 403 Mass. 441, 448 to 449 (1988). See also Commonwealth v. Troila, 410 Mass. 203, 206 (1991). Jeopardy does not terminate when a jury is discharged for inability to agree. Richardson v. United States, 468 U.S. 317, 326 (1984).

A judge who receives a report of deadlock may give the supplemental instruction drawn from Commonwealth v. Tuey, 8 Cush. 1 (1851), as revised in Commonwealth v. Rodriquez, 364 Mass. 87 (1973). The instruction asks each juror to reconsider in light of the views of the others, while telling every juror not to surrender an honest conviction merely because other jurors disagree.

There is a statutory limit in the other direction. Under G.L. c. 234A, § 68C, where a jury report twice after due and thorough deliberation that they are deadlocked, they shall not be sent out again without their own consent, unless they ask the court for some further explanation of the law. Commonwealth v. Tiscione, 482 Mass. 485, 492 (2019).

That limit is why the record supporting a deadlock mistrial often builds itself. The event that most clearly justifies stopping is the same event the statute says the judge may not push past. The deadlock in the Lindsay Clancy trial in Plymouth Superior Court followed that sequence.

Improper Evidence the Jury Should Not Have Heard

When a witness gives an answer the jury should not have heard, the ordinary sequence is a sustained objection, an order striking the answer, and a curative instruction. Jurors are presumed to follow a judge’s clear instructions and disregard the testimony. Commonwealth v. Auclair, 444 Mass. 348 (2005). See Commonwealth v. Cameron, 385 Mass. 660, 668 (1982); Commonwealth v. Gordon, 356 Mass. 598, 604 (1970).

Whether to declare a mistrial instead is within the trial judge’s discretion, and as long as the judge’s instructions are prompt and the jury do not hear the inadmissible evidence again, a mistrial is unnecessary. Commonwealth v. Kilburn, 426 Mass. 31 (1997), citing Commonwealth v. Gallagher, 408 Mass. 510, 517 (1990). See Commonwealth v. Canty, 466 Mass. 535, 545 (2013).

A motion for a mistrial on this ground therefore has to do more than identify the error. It has to explain why an instruction cannot cure it, which usually means showing that the jury heard something it cannot set aside, such as a reference to the defendant’s criminal record or to a confession that was suppressed.

Improper Argument by the Prosecutor

Improper closing argument is reviewed for its effect on the jury, and the errors are assessed together rather than one at a time. The prejudicial impact of a prosecutor’s argument is measured by the combined effect of the errors. Commonwealth v. Borodine, 371 Mass. 1, 11 (1976).

Some categories carry particular weight. A remark reasonably susceptible of being understood as a comment on the defendant’s decision not to testify is improper. Commonwealth v. Gouveia, 371 Mass. 566, 571 (1976). Most improper argument is nevertheless treated as curable by a prompt and forceful instruction.

Extraneous Influence on the Jury

Where a claim arises that the jury has been exposed to information not admitted at trial, or has been contacted by someone outside the courtroom, the judge must act. The procedure was set out in Commonwealth v. Jackson, 376 Mass. 790, 800 to 801 (1978), and reaffirmed in Commonwealth v. Tennison, 440 Mass. 553, 557 to 558 (2003).

The judge assesses the possible prejudicial effect of the exposure and weighs its impact by conducting an individual voir dire of each juror. Commonwealth v. Kamara, 422 Mass. 614, 616 (1996). Jurors may be asked what information came in and from whom. They may not be asked how they used it or what effect it had on anyone’s thinking, because that would examine the content of deliberations.

A judge has discretion in addressing extraneous influence discovered during trial. Commonwealth v. Trapp, 423 Mass. 356, 362 (1996). The remedy is often the removal of one juror and an instruction rather than a mistrial. A mistrial follows where the prejudice is irremediable. Commonwealth v. Kamara, 422 Mass. 614, 620 (1996).

Loss of a Juror

Illness, an emergency, or the discovery of a disqualification can leave a trial short of jurors. Before deliberations begin, an alternate ordinarily takes the seat. After deliberations have begun, a judge may discharge a deliberating juror only after a hearing establishes an emergency, another compelling reason, or an inability to perform the duties of a juror. G.L. c. 234A, § 39. The standard for the removal of a deliberating juror is demanding, and disagreement with the other jurors does not satisfy it.

A mistrial is not the only alternative even when no alternate remains. Under Mass. R. Crim. P. 19(b), 378 Mass. 888 (1979), where fewer than a full jury remain after jeopardy has attached, the defendant may waive the right to a full jury and request trial by the remaining jurors, by a signed written waiver filed with the court. Because that alternative exists, a judge who declares a mistrial over objection without considering it may have difficulty showing manifest necessity.

Misconduct Intended to Provoke the Motion

A defendant who moves for a mistrial ordinarily accepts a retrial. The exception is prosecutorial conduct intended to goad the defendant into moving for a mistrial. Where that intent is shown, double jeopardy bars the second trial even though the defendant asked for the first one to end. Oregon v. Kennedy, 456 U.S. 667, 679 (1982); Commonwealth v. Andrews, 403 Mass. 441, 447 to 448 (1988).

The standard is intent, not error. Serious prosecutorial mistakes, including the late disclosure of exculpatory material, ordinarily produce a new trial rather than a dismissal. Commonwealth v. Lam Hue To, 391 Mass. 301, 314 (1984).

Partial Verdicts

Where a jury has resolved some charges and deadlocked on others, the question is whether the resolved charges can be recorded before the mistrial.

Massachusetts Rule of Criminal Procedure 27(b) permits a jury, with the judge’s consent, to return a verdict on the charges or defendants as to which it has reached agreement, after which deliberations may resume. The rule is narrower than it sounds.

A judge is not required to accept a partial verdict before declaring a mistrial. Daniels v. Commonwealth, 441 Mass. 1017, 1018 n.3 (2004). And a judge is prohibited from taking one on a single indictment that contains lesser included offenses. Commonwealth v. Roth, 437 Mass. 777, 787 (2002).

Roth reasoned that a lesser included offense is part of a single charge rather than a separate charge, so a verdict on part of one indictment is not the general verdict Rule 27(a) requires. The court went further and instructed judges not to initiate such an inquiry at all, because the risk of coercing jurors is high and the reliability of a partial verdict extracted that way is low.

The distinction that survives is between counts. Across separate indictments a jury may return verdicts on some and deadlock on others. Within a single indictment carrying lesser included offenses, the judge may not ask. Where a not guilty verdict was in fact returned and recorded, double jeopardy bars retrial on that offense even if the judge should not have taken it. Commonwealth v. Roth, 437 Mass. 777 (2002).

A Verdict Exists Only When It Is Returned in Open Court

Jurors sometimes say after discharge that the panel had agreed on something it never announced. That does not create a verdict.

A criminal verdict is effective only when the jurors affirm it in open court. A Juvenile v. Commonwealth, 392 Mass. 52, 56 to 57 (1984). Posttrial accounts of private deliberations cannot retroactively alter the outcome of the trial, either to acquit or to convict. Read v. Commonwealth, SJC-13663 (Feb. 11, 2025).

The same decision declined to authorize an inquiry into what jurors said among themselves, because judicial examination of the content of deliberations is not permitted outside narrow exceptions for extraneous influence and for racial or ethnic bias.

Challenging a Mistrial

A defendant who believes a mistrial is about to be declared without manifest necessity may seek relief before a second trial begins. The route is a petition to a single justice of the Supreme Judicial Court under G.L. c. 211, § 3.

That relief is extraordinary and is exercised only in the most exceptional circumstances. Campiti v. Commonwealth, 417 Mass. 454, 455 (1994). The petitioner must demonstrate both a substantial claim that substantive rights were violated and an error that cannot be remedied under the ordinary review process. Planned Parenthood League of Mass., Inc. v. Operation Rescue, 406 Mass. 701, 706 (1990), quoting Dunbrack v. Commonwealth, 398 Mass. 502, 504 (1986).

The second requirement defeats most petitions filed while a trial is still under way. Interlocutory rulings in criminal cases are not ordinarily reviewed under the statute, because the rights of criminal defendants are generally fully protected through the regular appellate process. Morrissette v. Commonwealth, 380 Mass. 197, 198 (1980), quoting Costarelli v. Commonwealth, 374 Mass. 677, 679 (1978). The statute is not a substitute for normal appellate review.

A petition asking a single justice to stop a mistrial before it is entered is therefore harder than it appears. The double jeopardy claim is not lost when such a petition is denied. It can be raised by a motion to dismiss before any second trial, and the denial of that motion can be brought to a single justice at that point, when the claimed harm is imminent and the ordinary appellate process would come too late to prevent it.

Three things make the difference on such a petition. The objection has to be on the record. The record has to show the alternatives counsel asked the judge to consider. And the claimed defect has to be something other than disagreement with the judge’s assessment of whether the jury was truly at an impasse, because that assessment receives substantial deference.

What Happens After a Mistrial

A mistrial is not an acquittal. Massachusetts law generally bars a second prosecution for the same offense, G.L. c. 263, § 7, but that bar does not apply where the first trial ended in a mistrial supported by manifest necessity or by the defendant’s consent. Commonwealth v. Cassidy, 410 Mass. 174, 176 (1991).

The Commonwealth may ordinarily elect to try the case again, to resolve it, or to decline to proceed. A retrial begins from the beginning, with jury selection, new pretrial motions, and new evidentiary rulings, before a new jury that knows nothing about the first trial.

A mistrial returns the case to an earlier point in the Massachusetts criminal process. The charges remain pending, the conditions of release ordinarily continue, and the case is scheduled for trial again. Where a second trial produces a conviction, sentencing follows in the ordinary way.

For the defense, a mistrial changes the case in ways that can be used. Both sides have now seen the other’s evidence, the cross examinations, and the arguments that worked. Testimony given at the first trial is available for impeachment. Rulings that went badly can be relitigated on a better record.

Talk to a Lawyer About a Mistrial

Attorney Joe Serpa defends criminal cases in the District Court, the Boston Municipal Court, and the Superior Court, and handles the trial and posttrial motion practice that a mistrial produces. To discuss a case that ended without a verdict, or one that is heading toward a second trial, contact Serpa Law Office for a free consultation. Case outcomes are collected on the Massachusetts criminal defense results page.

Serpa Law Office can be reached at 617.936.0201.