It seems to me that if the phone's owner (Walker) wants the phone turned over to the police for any reason, then his lawyer's possession should be terminated. Gay is using the phone for some purpose, but the owner wants it used by a different agency for a different purpose.
Why should the lawyer be allowed to hold onto the phone against the owner's wishes? Semantically, this is theft on the lawyer's part in my mind.
The police are not your friends and the search of Gay was not find favor to Walker.