The parties bear the same substantive burden of proof as would apply at a trial on the merits, including plaintiffs burden to establish any element essential to his case. Liberty Lobby, 477 U.S. at 252; Celotex, 477 U.S. at 322; Taylor v. List, 880 F.2d 1040, 1045 (9th Cir.1989). y The plaintiffs complaint against defendant WNS alleges that it violated his Fourth, Eighth, Thirteenth and Fourteenth Amendment rights by “caus[ing] and allowing him] to be sexually ass[a]ulted and brutalized ... through policies, customs, procedures and unlawful practices.” Complaint at 3. Although the plaintiff cites the Fourth, Eighth, Thirteenth and Fourteenth Amendments, his claim properly arises solely under the Fourth Amendment. See Pierce v. Multnomah County, Oregon, 76 F.3d 1032, 1043 (9th Cir.) (<HOLDING>), cert. denied, - U.S. -, 117 S.Ct. 506, 136
holding neither a phone call by the police requesting an arrestee to come to the station for questioning nor the questioning of an arrestee at the station was a seizure within the meaning of the fourth amendment holding fourth amendment protects right to be free from arrest without probable cause holding that warrantless arrest based on probable cause did not violate the fourth amendment holding that the fourth amendment sets the applicable constitutional limitations on the treatment of an arrestee detained without a warrant up until the time such arrestee is released or found to be legally in custody based upon probable cause for arrest holding that a warrantless arrest does not violate the fourth amendment if at the time of the defendants arrest police had probable cause to believe that an offense has been is being or will be committed