How couldsomeone sabotage my wheels?

I have a 2004 chevy blazer and the wheel on the right locked up. When I would be out shopping and came back to my car, several different times someone in the parking lot would tell me that someone was messing around my car wheel. I only looked for flat tires, I didn't know someone could sabotage the wheel. apparently the bearings or something locked up. The mechanic said it was a common problem but I don't believe him. What could someone have done to the wheel to make that happen? Thanks.

Your mechanic can tell you.
Ask to see the old wheel bearing and tell us what you find on or in it.