Explainer

Material Witness and Suspect. What’s the Difference?

CNN reported last night that three people taken into custody in an FBI raid in Boston are material witnesses to the terrorist attacks but that investigators say they are not suspects. What’s the difference between a material witness and a suspect, and can both be held in custody?

A material witness is someone who possesses facts about a case that could be helpful to law enforcement investigators, but who was not part of the criminal activity and did not knowingly assist in it. In this case, the men detained–they were later released–used the same credit card that was used to buy airline tickets for some of the hijackers. “Material witness” is law enforcement parlance; lawyers refer to such a person as a “subject.” Suspects (or “targets” as lawyers call them) are people believed to have been involved in the criminal activity. An individual’s status can change from material witness to suspect if information comes to light that shows the person’s complicity in the crime. In that case, a person can be charged as an accomplice, which for legal purposes can make him as culpable as the actual perpetrator.

Law enforcement officials can detain people for a few hours without filing charges, but holding someone in custody for a long period requires formal charges. [Explainer Clarification: That’s wrong. Click here for the actual rules for holding material witnesses.] It’s common for people being questioned as material witnesses to cooperate with law enforcement. For those who are reluctant to talk, a threat of being charged as part of a conspiracy often melts that reluctance. During yesterday’s raids around the country, there were individuals picked up in connection with the attacks who were found to have problems with their immigration status. People in the United States illegally can be detained for lengthy periods for immigration violations alone.

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Explainer thanks Frank Carter, an attorney in private practice inWashington,D.C., and Jennifer Lyman ofGeorgeWashingtonUniversityLawSchool.