What happens to a priest if he wont reveal a secret of confession to the police?

Hello, I was wondering what would happen to a catholic priest if he would not reveal a secret of confession to the police. For example, lets say the police or FBI are investigating a suspected killer or International drug dealer, and that suspect tell a catholic priest that he is a killer or an international drug dealer, but as a secret of confession. The FBI or police are positive that the priest knows enough info about the suspect to lock him up, but because he is a priest, the priest refuses to tell the FBI what he was told by the suspect under the secret of confession, what would happen. Would the priest be convicted for some reason like blocking an ongoing investigation, or would he be considered an accomplice. Thank you in advanced.