!Factors that can influence jurors in criminal trial

Criminal defendants have a right to trial by an impartial (non-biased) jury, and juries are supposed to decide cases based only on the evidence presented in the courtroom. However, in reality, outside forces can and do reach jurors. Whether it's a juror scrolling through social media during trial, an offhand comment by a court clerk, or a bribe, outside influences can quietly undermine a defendant's right to a fair trial. Remedies range from curative instructions to a new trial.

In This Article

What Is Jury Tampering?

Jury tampering happens when someone outside the jury tries to improperly influence how a juror will decide a case. Being successful in one’s attempts isn't necessary for a conviction.

Common Examples of Jury Tampering

The most obvious example of jury tampering is bribery—offering a juror money or something of value to vote a certain way. But jury tampering takes many other forms, including:

  • threatening a juror or a juror's family member
  • leaving anonymous notes for a juror
  • slipping a juror photographs or documents that weren't admitted into evidence, or
  • telling a juror information the judge specifically excluded from trial.

Any attempt to sway a juror's vote—subtle or not—can constitute jury tampering. The person influencing the jury or juror doesn’t have to be an outside party. It can be a court officer, bailiff, witness, or court clerk.

Criminal Charges

Jury tampering can carry serious criminal charges. For instance, California and federal law make jury tampering felony-level offenses. (18 U.S.C. § 1503; Cal. Penal Code § 95 (2026).)

What Counts as Juror Misconduct?

Juror misconduct is different from jury tampering. It refers to a juror's own improper behavior—not something done to the juror.

When Juror Misconduct Is a Crime

Juror misconduct can be a crime if it rises to the level of promising or agreeing to vote one way or another. Arizona, for instance, makes this type of juror misconduct a class 6 felony. (Ariz. Rev. Stat. § 13-2808 (2026).)

When Juror Misconduct Jeopardizes a Trial or Verdict

More often, juror misconduct refers to disobeying a judge’s instructions about how to conduct themselves and what to do or not do. This type of misconduct isn’t generally a crime, but it can taint the juror or jury and jeopardize an entire trial or verdict.

When jurors are sworn in, the judge instructs them not to discuss the case with anyone, not to research the case on their own, and not to seek out information beyond what's presented as evidence. Jurors can’t even talk about the case to each other until they’re in deliberations.

Common Examples of Juror Misconduct

Common examples of juror misconduct include:

  • talking about the case outside the courtroom, such as discussing the case with a spouse, friend, or coworker before the jury reaches a verdict
  • conducting independent research, such as visiting the crime scene, looking up the defendant online, or reading news coverage of the trial
  • using social media to post about the case or jury service or to read posts and comments about the trial
  • lying during jury selection (voir dire), including concealing bias or relevant personal history when answering the judge's or attorneys' questions
  • discussing the case with other jurors before deliberations start
  • harassing or improperly trying to influence fellow jurors to vote based on biases, and
  • not paying attention to the trial, whether by sleeping, being intoxicated, or otherwise being distracted.

Breaking any of these rules is juror misconduct. (N.C. Gen. Stat. § 15A-1236 (2026).)

Social Media Challenges in Jury Trials

Judges routinely instruct jurors not to use social media to research or discuss the case—and for good reason. Social media doesn't just enable juror misconduct, it can also be a vehicle for outside parties to tamper with a jury.

Federal jury instructions explicitly warn jurors that when they access email, social media, or the internet, they might encounter targeted ads or pop-ups related to the case, legal principles, or connected issues—all of which can introduce bias without the juror even realizing it.

The risk runs in both directions. A juror who posts about the case may unwittingly invite responses from strangers, journalists, or people connected to the parties. And a juror who simply scrolls their feed may encounter news coverage, opinion pieces, or comments that color their view of the evidence. Courts treat both as serious problems. Violating a judge's social media instruction is misconduct—even if the juror believed the posts or browsing were harmless.

Accidental Influence Over a Juror

Not every instance of improper influence involves someone breaking a rule. Sometimes a juror is improperly influenced through no fault of their own—and without anyone committing jury tampering or misconduct.

For example, say a juror accidentally overhears a conversation between two attorneys in a courthouse hallway about evidence the judge had ruled inadmissible. The juror didn't seek out the information. No one tried to influence them. But the juror has now been exposed to something they weren't supposed to know, which could affect their judgment.

In situations like this, judges have to assess whether the accidental exposure was likely to affect the juror's ability to be impartial, even when nobody did anything intentionally wrong.

What Happens When a Juror Is Improperly Influenced?

When a judge learns that a juror may have been improperly influenced—through tampering, misconduct, or by accident—the court has several options depending on how serious the situation is. Here are a few of them.

Cautionary Instruction

For minor issues, the judge may remind the jury to disregard outside information and continue with the trial.

Dismiss and Replace the Juror

If the judge decides a particular juror can no longer be impartial, the judge may remove that juror and seat an alternate.

Declare a Mistrial

If the improper influence is serious enough that no remedy short of starting over will protect the defendant's right to a fair trial, the judge can declare a mistrial. This ends the current trial without a verdict, and the defendant can be retried before a new jury.

Set Aside Verdict and Order a New Trial

Misconduct discovered after a verdict may warrant setting aside the verdict and ordering a new trial, when it substantially prejudiced the outcome of the trial or undermined the fairness of the trial.

The right remedy depends on the specific facts—the nature of the influence, how damaging it was, and whether it likely changed the outcome. Not every instance of outside contact leads to a mistrial or new trial. Judges generally have broad discretion in deciding what corrective actions to take.

How Courts Decide Whether to Declare a Mistrial or Order a New Trial

Courts consider declaring a mistrial, setting aside a verdict, or ordering a new trial to be drastic remedies. A judge will generally only order such a remedy if the tampering, misconduct, or influence had a prejudicial effect on the defendant's right to a fair trial.

Judicial Investigation

The judge must first assess the credibility of the misconduct or tampering allegations and investigate whether it involved a consequential issue. In clear cases of prejudice, the judge may declare a mistrial or order a new trial immediately. In less obvious instances, the judge may conduct an investigation, questioning jurors to determine the nature of the misconduct. It’s then up to the judge to determine how the misconduct likely impacted deliberations or the verdict.

No-Impeachment Rule

Importantly, jurors can’t testify about statements made during deliberations or what their internal thought processes were. This is called the no-impeachment rule. It exists to protect the finality of verdicts and allow jurors to deliberate in an honest and candid manner.

However, the no-impeachment rule will take a backseat if substantial proof exists that racial bias was a significant factor in a juror’s vote to convict. The Supreme Court made this exception stating that “racial bias in the justice system must be addressed…[and] is necessary to prevent a systemic loss of confidence in jury verdicts….” (Peña-Rodriguez v. Colorado, 580 U.S. 206, 222 (2017).)

What to Do If You're a Juror Who Was Contacted

If you're a juror and someone (friend, stranger, court official, or any third party) contacts you about the case:

  • Don't respond. Don’t engage with the person or the information in any way.
  • Tell the judge immediately. Report the contact to the judge or court clerk as soon as possible, before the next court session if you can.
  • Don't discuss it with other jurors until the judge instructs you to do so.

Reporting outside contact protects both you and the integrity of the trial. Judges are experienced at handling these situations—and they'd rather know about a problem early than deal with a mistrial later.