A city did not fail to supervise a police officer who allegedly raped a victim while on duty, and thus was not subject to § 1983 liability. The victim only identified one prior sexual assault complaint against the officer’s unit, which was not against the officer and which the complainant did not pursue, and there had been only four total sexual assault complaints against the city’s police department in the past twenty years. Those undisputed facts could not establish a constitutionally deficient failure to supervise, and the victim could not show the required widespread pattern of constitutional violations to establish that the city’s actions or inactions amounted to a deliberate indifference to the danger of the officer sexually assaulting the victim.