Lowell Harris was the main antagonist in the Law & Order: Special Victims Unit episode "Undercover".
Harris was a prison guard at the Sealville Corrections Facility. He had secretly violated and took advantage of several women prisoners, including Ashley Tyler. Upon learning of Ashley's story after hearing that the rape kit is missing and believing that one of the guards is responsible for brutalizing the women, Detective Olivia Benson (one of the protagonists of the series) went undercover as an inmate to find out. However, she almost end up being a victim when Harris took her down to the facility's basement and attacked her. He then attempts to rape her by forcing her into oral contact, until Detective Fin Tutuola (who went undercover as one of the prison guards) stopped him from advancing. The detective then arrest Harris, but during interrogation, the prison issued an attorney for him and got him off since he was unaware that Benson was a cop. However, Ashley identified a mole on his penis, which she couldn't have possibly knew unless he showed her. And since Benson had actually seen it before she was almost raped, this provided a warrant for the detective to finally arrest Harris for Ashley's rape and Benson's attempted murder. Even the warden (who is a woman herself) is completely disgusted by Harris' actions, ordering the detectives to get him out of her prison for good. Upon seeing the detectives arresting Harris, several of the female inmates cheered for this. Harris is then sentenced to 20 years to life in prison for his crimes.