OnPlayerSpotted???

[Your Computer]

When the monster gives up searching for the player, it returns back to where it started and continues on its path (set by path nodes). The monster will get deactivated if the player is out of the monster's activation distance and if the player isn't staring at it. Reactivating the monster after it's been deactivated depends on whether or not it killed the player (though my memory on this is a bit lacking).