Is a police officer who takes advantage of a detainee's lawful restraint and engages in sexual acts for the improper purpose, such as sexual arousal or gratification, unlawfully restrain the detainee?

A police officer who takes advantage of a detainee's lawful restraint and "engages in acts for an improper purpose, such as sexual arousal or gratification . . . is unlawfully restrain[ing the detainee] during the illegal acts." (People v. Alford (1991) 235 Cal.App.3d 799, 804 [physical restraint of female inmates being transported between correctional facilities, although initially legal, became illegal during period when transporting officer sexually assaulted female inmate].)