Your character is at the mall / supermarket / farmer's market one afternoon when a man in a black leather jacket walks up to another man, pulls a gun with a silencer, and shoots him at point blank range. The victim dies instantly, and the shooter slips into the shocked crowd. But your character manages to catch up with the shooter, who surprisingly surrenders without a fight. Upon questioning, the shooter reveals that he is a precognitive telepath, and that he'd had a vision of the victim committing a mass shooting at that same mall / supermarket / farmer's market later that same day. He argues that he saved more than 30 lives by taking out the shooter first.
What does your character do?