[ttt11199907]

Would it still be theft if the money in your wallet was money that you found on the street the day before?

[Terr_]

Huh? Thieving from a thief is still theft, the same way that raping a rapist is still rape.

(Also even when a wily Sicilian complains that "You're trying to kidnap what I've rightfully stolen".)

[pi-e-sigma]

You are wrong. In most jurisdictions theft is defined as taking something away from the legal owner. If what you said was true then taking away your own property from the thief who stole it would also be a theft.