What is the burden of proving effective consent to a search warrant?

The Government bears the burden of proving effective consent. United States v. Impink, 728 F.2d 1228, 1232 (9th Cir.1984). A consensual search is reasonable when the consent-giver has "common authority" over the area searched. United States v. Matlock, 415 U.S. 164 (1974). "Common authority" rests on mutual use of the property by those generally having joint access or control so that it is reasonable to recognize that any of the parties has the right to permit inspection and others have assumed the risk that the third parties might consent to the search. Id. at 171 n. 7; United States v. Yarbrough, 852 F.2d 1522, 1534 (9th Cir.), cert. denied, 488 U.S. 866 (1988).

A warrantless search is also justified when the authorities have reasonable grounds to believe the person giving consent has the apparent authority to do so. United States v. Sledge, 650 F.2d 1075, 1077-78 (9th Cir.1981). In making this determination, the court should consider (1) whether the third party has an equal right of access to the premises, (2) whether the suspect is present at the time the third party consent is obtained, and (3) if so, whether the suspect actively opposes the search. United States v. Warner, 843 F.2d 401, 403 (9th Cir.1988) (citation omitted).