You are a police officer. while you were driving you parked at a coffee shop. You wanted to check the alleyway because you are weirded out about it. You see a man with blood at his month and hes looking down the body he killed. He looked at you and showed fear

"Its not what it looks like! He... He came after me- and- I don't-"

He is scared and stuttering. What do you do to calm him down?