"That's a very old trick. Because lots of people think that the hero of an incident is above suspicion. So sometimes criminals set up crimes to make it look like they were the heroes that came to stop it."

Conan had seen that trick over and over, in many different variations. The arsonist who came to put the fire out, the murderer who called the ambulance and tried to use detectives and police officers as alibis, the thief who claimed to be a bystander injured in a fight with the culprit...