A person is guilty of theft if he:
1. Retains or disposes of property of another when he knows it has been lost or mislaid; or 2. Retains or disposes of property of another when he knows it has been delivered under a mistake as to the identity of the recipient or as to the nature or amount of the property, and with intent to deprive the owner of it, he fails to take readily available and reasonable measures to restore the property to a person entitled to have it.