Though the better analogy might be: Bob knows that somebody is out to kill him and so he hides at the police station while a cop places a mannequin in his bed and waits in Bob’s closet for the murderer to show up. Or, more commonly, the cop goes undercover and poses as a hit man and gets the murderer on tape contracting the hit. That’s a pretty common sting and people get first degree murder convictions out of it.