4th Circuit: Suspect in custody doesn't have to wait until Miranda rights are read for his assertion of the right to remain silent to have full effect (requiring officers to stop the interrogation, or in this case never to start it). ca4.uscourts.gov/opinions/17423… 
As I understand the court's opinion, you can assert your Miranda right as soon as you are in custody, but you don't have to wait until you are given warnings or questioned. (This is a question that students often ask about, so good to have a case to cite to them.)
Also interesting that the 4th Circuit has a five-factor test for when an officer's post-invocation conduct sufficiently honors the assertion of the right. (For those who don't know, "five factor test" mostly means "no test at all"). CA4 right to cabin that inquiry more here.
