What Is an Immunity Deal? A Guide to Legal Immunity in Criminal Cases

When a person has been implicated in a crime, they can sometimes help themselves by testifying against accomplices in exchange for a lighter punishment. But this kind of deal isn't the only way prosecutors can get a person to testify. Sometimes prosecutors can compel testimony from reluctant witnesses by granting them legal immunity. Immunity removes a witness' ability to invoke the Fifth Amendment, meaning they face a choice between testifying and potentially going to jail.

In this article we'll explain when prosecutors grant immunity, what an immunity deal means for the witness, and how an immunized witness might still end up in trouble with the law. Not all people who are granted immunity are suspected of serious wrongdoing--sometimes their reluctance to testify is based on factors like a fear of retaliation, or loyalty to a friend or family member. So if you've been asked to testify in a criminal trial, or might have evidence you're reluctant to share for any reason, it's important to understand how legal immunity might apply to your situation.

What Is an Immunity Deal?

A witness who is asked to provide information that could be incriminating in any way can normally invoke the Fifth Amendment privilege and refuse to answer. A question is incriminating when it calls for an answer that provides either:

• direct evidence of a crime (for example, "I robbed the bank") or
• information that could lead to evidence of a crime (for example, the name of someone who could testify to the fact that the witness robbed the bank).

But if prosecutors feel the witness' testimony is important enough, they may grant the witness immunity. Immunity means that a witness' testimony can't be used in a criminal prosecution against them. This means they can no longer assert their Fifth Amendment right not to testify, and can be held in contempt of court if they refuse to answer questions.

Immunity isn't the only option prosecutors have when they want testimony from someone who they think has committed crimes. Prosecutors can also make agreements with potential witnesses. This can happen, for example, when a witness agrees to testify against an accomplice as part of a plea bargain promising them a more lenient sentence.

As the United States Department of Justice (DOJ) notes, the key difference here is that:

• a grant of immunity forces a witness to testify (or face criminal consequences) by preventing them from invoking the Fifth Amendment, but
• a deal between prosecutors and a witness is voluntary.

A deal between a prosecutor and a particular witness does not grant the witness the same broad protections against future prosecution as a grant of immunity. As the DOJ notes:

• a grant of immunity creates a Fifth Amendment barrier to the use of that testimony in other jurisdictions, but
• a deal between a prosecutor and a witness only binds the jurisdiction where that prosecutor works.

This means, for instance, that a federal grant of immunity prevents state courts from using a witnesses' testimony against them, but a deal between a federal prosecutor and a witness would not.

How Do You Get Immunity in Court?

Immunity from prosecution is an important tool for prosecutors. They can grant immunity to witnesses for all types of crimes, even serious ones like kidnapping and murder. But prosecutors only grant immunity in specific circumstances. For example, federal law specifies that prosecutors should only grant immunity when:

• the witness' testimony (or other information) may be necessary to the public interest, and
• the witness has refused to testify (or isn't likely to testify) because of their Fifth Amendment right against self-incrimination.

(18 U.S. Code § 6003 (2025).)

To decide if granting immunity is in the public interest, the DOJ directs prosecutors to consider factors including:

• the importance of the investigation or prosecution to effective enforcement of the criminal laws
• the value of the person's testimony to that investigation or prosecution, and
• the person's criminal history and how much culpability they have for the crimes being investigated or prosecuted.

Prosecutors at the state level use similar criteria to decide when to grant a witness a immunity.

A grant of immunity compels a witness to testify, even if that testimony implicates them in crimes. It is therefore vital that the terms of any immunity deal be carefully negotiated between the government and the witness' attorney. Failure to do this risks a situation where a witness thinks they have greater protections than they actually do, and could allow their testimony to be used against them.

What are the Limits on Witness Immunity?

As we discussed above, there are two main types of immunity. The broadest type, transactional immunity, means a witness can't be prosecuted for the criminal acts they discuss in their testimony. But this type of immunity is much less common than so-called "use and derivative use" immunity, which offers narrower protections. Use and derivative use immunity only prevents prosecutors from using a witness' testimony against them. It doesn't prevent prosecutors from conducting separate investigations to uncover other evidence of the witness' criminal acts, or from prosecuting the witness for those acts.

(Read more about the two main types of immunity.)

In addition to these limits on the kinds of immunity a witness can receive, there are other circumstances where an immunized witness might still be prosecuted.

Failing to testify fully and truthfully. Once a witness is granted immunity, the law expects their testimony to be honest and complete. Like other states, California allows the state to prosecute immunized witnesses for perjury if they lie while testifying, or for contempt if they refuse to answer certain questions.

Waiving immunity. Because immunity is a privilege, it can be waived. Sometimes a person might voluntarily waive immunity. But it can also be waived by accident. For example, if a witness repeats the contents of their immunized testimony outside of court, or in a different proceeding, it could end up being used against them.

Civil proceedings. Immunity protects a person's Fifth Amendment right against self-incrimination. It does not mean that immunized testimony can't be used outside of criminal court. So, for example, if someone is sued for the same actions they testified about under a grant of immunity, that testimony could be used against them in civil court.

Consult a Lawyer

When prosecutors compel testimony using a grant of immunity, it puts the witness in a high-stakes and legally complicated situation. Anyone at risk of prosecution would benefit from consulting an attorney. But it's particularly important to work with an experienced criminal defense attorney if you've become involved in a criminal investigation and the government may use immunity to make you testify.