Dz. has been provided with an attorney - so somebody is advising him of his rights. His lawyer is obligated to tell him he doesn't have to talk.

He faces Federal charges of premeditated murder with an explosive device in an act of terror. There will be other charges, including state charges in Massachusetts. The Federal charge carries a potential death penalty even if state charges do not.

As an American citizen arrested on American soil, it appears so far that he will be tried in civilian court with full Constitutional protections.