For this story, we must go back a number of years, to my very first job when I was still in high school. I was working at a large drug store chain, and after a couple of months I was trusted enough that when our store manager transferred to another state, he left me the store keys to bring to the new manager the next morning. (No, I was absolutely not officially entitled to carry the keys.)
It didn't take long before I had a similar level of trust with the new manager, so when one of our cashiers began displaying some unusual habits, I was clued in to help figure out the mystery.
This particular cashier worked in the afternoon and evening, as she was a student at a nearby bible academy. Usually she would work until closing, and the manager noticed that every night after work, she would drive completely around the shopping center, then drive to the back and disappear.
My manager suspected she might be stealing something, so one day he had her take the trash out to the dumpster. Then I got to climb inside and check the bags to see if there was any merchandise in there. We did this a few times, but I never found anything.
Finally, one night the manager watched her make her usual circuit around the store and before she continued to the back, he drove off. He waited about ten minutes, then drove back to the shopping center and too a look behind the store.
What he saw was Miss Bible Academy and her boyfriend engaged in -- well, let's just say what they were doing would not have met with the approval of the school faculty.
She called the next day and quit.