The illegal Mexican who admitted he was looking for work wrapped a gun in a t-shirt, walked halfway out onto a pier, attempted no robbery, shot her three times, shot no one else including her father standing right next to her, and left. That's a hit.
I suggest you avoid crime fighting and psychology as professions, although you'd probably do great as a writer in Hollywood.
That was my thought. An obvious crazy might just be the perfect hit man. Caught, he probably can’t finger the principal and in SF it might be considered non PC to even ask.