A really bad thing happened in a place I worked at years ago. We had a terrific team spirit which was required given this was an operating theatre in an A&E hospital so we never knew what was coming through the doors next. Anyway, somebody did the worst thing that can be done to disrupt and ruin a team and start incriminations, denouncements and suspicions; this person stole from his/her (we didn't know at the time) colleagues!
Of all people, it was my wife (way before we'd become romantically linked) who pointed out who it was. Mind you, she'd have made a great detective, I can't get away with the slightest misdemeanour!
It turned out to be one of the longest-serving nurses who worked with us and she had no shame in stealing money from purses or out of other nurses' lockers. Some of her best friends fell victim to her thievery.
One fellow technician came under suspicion by the very thief that turned out to be the guilty one and he offered to turn out his pockets and give us the key to his locker but we unanimously refused as we knew with absolute certainty it wasn't him.
So eventually, the big boss obtained some indelible powder from the police and coated two five pound notes with is and the guilty nurse was caught literally green-handed! We all wanted her to be sacked as there were some real sad results of her theft. Some nurses couldn't afford bus fare home and one had filled up her car knowing she had enough to pay but her purse had been emptied before she got there!