How did they figure three people were involved?

I'm guessing it was probably the crew doing the closing cleanup that night.
Probably ratted each other out when they got caught.

They should have put them in jail, with nothing but their own special lettuce to eat!

Hey that's my old stomping ground.

I wonder how often this kinda stuff goes on and nobody gets caught?
I talked to a woman who managed a (different) fast food joint at one time who said it was all she could do to keep the boys from pissin' in the pickles.
Seems to me there's gotta be laws against this stuff that require more than getting fired.