daf bit: Bava Metzia 26

[cellio]

Raba said: if a man sees another drop a coin and he takes it before the owner has abandoned it (that is, given up hope of finding it), he transgresses three commandments: do not rob, do restore, and do not hide yourself. If he returns it after abandonment, it is treated as a gift, not a return of lost property, and his transgressions stand. If when he picks it up he intends to return it, but changes his mind when the owner abandons it, he violates the command to restore (only -- he did not have the intention to rob). If he waits for the owner to abandon it and then takes it, he violates only "do not hide yourself". (26b)