A criminal suspect has a Fifth Amendment right not to be compelled to incriminate himself, so he cannot be forced to make a statement. But if he is lawfully in custody, he can be compelled to submit to particular tests or to provide exemplars of his physical attributes. Under some circumstances, he can also be compelled to behave in certain ways ("modeling") in order to assist in identification.
Modeling, testing, and exemplars can be obtained by voluntary compliance with police requests, or in response to a grand jury subpoena, or by court order. If the suspect refuses, the prosecution is generally free to argue to the jury that the refusal constitutes consciousness of guilt.








