From your description of the facts, there apparently was a pre-existing arrangement between the thief and the defendant for the latter to purchase the stolen goods from him. If one purchases, or receives as a gift goods that are stolen knowing that they are stolen, then he is guilty of the charge. The obvious defense would be entrapment; however that defense would not lie in this case. Entrapment only lies if the defendant is induced to commit a crime which he was not predisposed to commit beforehand. In the present instance, there appears to have been some predisposition on behalf of the defendant. The fact that the thief delivered more radios than he had in fact stolen is no defense. Even if the radios furnished by the police were not stolen goods the first three were in fact, and the offense is consummated. Had he ONLY delivered the eleven radios furnished by the police, he would be not guilty, as the goods were not stolen.