In criminal law, there are two types of immunity. The first is called “use immunity” and the second is called “transaction immunity.” These kinds of immunity provide varying degrees of protection.
In general, transaction immunity is much broader, and therefore far more protective. Generally immunity is offered by a prosecutor in exchange for something, whether it’s a chance to talk to a witness/suspect or a chance to have that person testify before a grand jury or in a courtroom.
Use immunity serves the limited purpose of permitting a person to offer information to police, investigators or prosecutors. It bars the prosecutors from using those statements against the witness/suspect in the future. The idea is that by cooperating, someone can get either a better plea offer or a reduction in sentence, and that such statements will not be used against the witnesses, except to impeach that person’s testimony should that person ever change his or her statements.
Transaction immunity serves the broader purpose of protecting the person against any criminal liability arising out of that transaction. So, for instance, if the person is testifying about what he saw, and it later comes to pass that the person was actually involved in the commission of the crime, transaction immunity would protect that person from criminal liability.
It’s important to remember that the state of North Carolina is not in a position to grant transaction immunity on behalf of the federal government, and the federal government is not in a position to grant transaction immunity on behalf of the state of North Carolina.
What that means is that if you are granted transaction immunity by the state of North Carolina, that would not prevent the United States Government from prosecuting you.
Nonetheless, transaction and use immunity are two ways of protecting oneself from criminal liability if one wants to cooperate with investigators.