Suspect of Opportunity
FEAT 10 reaction
A creature who isn't, to your knowledge, tied to any of your active investigations takes a hostile action against you in combat.
Sometimes something intrudes upon your case unexpectedly, such as an ambush sent to bring your investigation to a close. You use Person of Interest against the triggering creature. This doesn't allow you to use Person of Interest more frequently than normal.
Pathfinder Player Core 2ORC