Asshole

it's a MADE-UP joke... HR to investigate stolen sandwich?? but pretty OK office joke...

If it weren't a joke, I'd haul his ass out of the building. Then stuff a fresh sandwich up his ass with a plunger.

You'd be really surprised the kind of minor nonsense people have lost their jobs over. Stealing personal property is generally an offense that can lead to termination.
Even threatening to steal someone's lunch can get you fired these days.

Unless you're black.

Then that would be discriminatory...

.