Detectives will typically ask to speak to you for one of two reasons: either they believe you witnessed a crime or you’re a suspect in a crime they are investigating. I am going to briefly discuss the second scenario.
By the time a detective contacts you there’s a pretty good chance you’re the prime suspect. In my experience detectives often get tunnel vision when they like a suspect for the crime they are investigating. When this happens, they hyper focus on one person and one theory of the case while ignoring other suspects and other evidence. You can see how this can cause problems for innocent people.
You can refuse to talk to a detective at any time. They will probably not leave you alone, but you do not have to talk to them; even if you're arrested (see more on this below).
When a detective wants to talk to you because you’re a suspect, they will generally be very nice and even friendly. They will say things like, “I just want you to come down and help me clear up some confusion. I already know you didn’t do it. But I’d appreciate it if you could help me out. It won’t take long, and you’ll be in an out really quick.”
It could be that none of that is true!
Detectives and other police can legally lie to you. They do it all the time. I have had many clients who were lured into the police station by a friendly detective and never walked out. They want you to come to the police station voluntarily and ultimately, they want you to confess.
They will probably first attempt to get you to admit you were near or at the scene of the crime, which will only convince them further that you did it. They may lie and say, “A couple of people already told us they saw you there.” Or they might say, “We have you on video.”
Again, these are very often complete lies. Detectives are trained in the art of interrogation. You are not.
The point is this: if you go to the police station voluntarily, you are not under arrest. And the detectives will sometimes say things like, “You can go at any time, but I’d like to hear more.” As long as you are free to leave, you are not under arrest. That is the legal test.
Detectives don’t want to arrest you immediately for a couple of reasons. They may not have enough probable cause to arrest you, and once you are arrested two things happen automatically: you have the right to remain silent and you have the right to have an attorney present during all questioning.
Detectives do not want either thing to happen. If you don’t talk, you don’t help them get evidence they will use against you, and if you have an attorney present, it is doubtful you will be allowed to say anything that helps the police (and thus hurts you).
My advice is this: never voluntarily speak to a detective without having an attorney present. This is true even if you’re 100% innocent. This might shock you, but innocence doesn’t matter; not even in a courtroom. I have had innocent clients who jammed themselves up by talking to detectives, and I have had innocent clients convicted at trial.
Innocence helps, but it’s ultimately not the deciding factor in a criminal case.