So, this happened over a decade ago.
I was working in a clothing store, and it was a pretty great gig. I had decent hours, I got a 50% discount… the only drawback was one of my co-workers. I’ll call her Bea. Bea was one of those people who would be pleasant, then would suddenly say something nasty and laugh it off. She would leave me nasty notes (things that said, “How stupid are you? How did you not know X") or would simply make the comments straight to my face. I talked to my manager about it, who talked to Bea, but not much was done.
Eventually, a promotion became available, and both Bea and I were up for it. We both were interviewed, and eventually, I got the position. I felt pretty good about that, but it only made the bullying worse.
Eventually, one night, when I was closing, I realized that there had been a trend that had been going on for a while. Bea would have a return, but the slip with the customer information would be missing. I was a little frustrated (and, if I’m honest, smug, because I always kept track of that slip) but then a thought occurred to me. I pulled out a receipt from a sale I did to Bea earlier and compared the card numbers, and lo and behold, they matched.
I was in a state of shock. I called my manager and explained what I had found. She had me go back through the last few weeks sales to see if I could find any more.
When Bea arrived at work the next morning, the police were waiting in the back room. I wasn’t allowed to be anywhere near the store, because they were worried she'd retaliate. I don’t know all the details of her punishment (I purposefully kept myself distanced), but I heard something about her having to repay them.
It doesn’t end there though.
A few months later, I was shopping at the other mall in town, and saw Bea working for another clothing store chain. The next day, I went by the store in our mall and chatted with my friend who worked there. I “casually” mentioned that I noticed Bea was working there now, and asked what she thought of that.
My friend said that she didn’t know too much since Bea worked at the other location, but then asked if I knew anything she should know.
I said that I didn’t want to cause anyone to lose a job, but that doing a criminal record check on any new employees would be a good idea. Next thing I knew, Bea didn’t work there any longer.
TL;DR I found that my bully was a thief and definitely cost her one job, possibly two (though if she didn’t steal she wouldn’t have been fired so maybe she cost her the jobs, but…)
Edit: For the refunds, she was waiting until the floor was clear, then grabbing merch off the racks and doing a refund onto her card. Then she was throwing out the slip of paper that was supposed to have the client information written on it, so that we can keep track of all that (and probably to prevent this from happening).
In the end we had to do a store inventory because they had no idea how much of what items we actually had, because the system thought we had much more of whatever she "returned" but (of course) there was no physical product to go with that.