What to do when you are called in for questioning

Lately I've been on the road quite a bit and I'm listening to John Grisham's The Innocent Man. A small town Oklahoma police department and prosecutor "solved" two murders back through coerced confessions. A painful, gripping book. As I'm listening I think, if you are ever called in for questioning, ask for an attorney immediately even if you are innocent and think all you have to do is tell the truth.