All written by brilliant, if PC idiotic, writers. Not saying it never happens, but I believe the first prize for true evil genius ought to go to prosecutors’ offices (they’re the folks who make the twisted cases in the courts), and sometimes to cynical judges, but seldom to police and detectives.
I think you’re right. But it’s still a good idea to be very careful what you say to the police, because they’ll put it in their report and then the prosecutors will have more stuff to twist and distort.