In 1991, NIS was responsible for investigating the Tailhook scandal, which involved allegations of sexual misconduct and harassment by Naval and Marine Corps officers in Las Vegas, Nevada. Subsequent to this investigation, and at the direction of the chairman of the US Senate Armed Services Committee, Senator Sam Nunn, the Naval Investigative Service was restructured into the Naval Criminal Investigative Service (NCIS). The restructuring occurred as a result of perceived lapses in proper investigative technique over the Tailhook scandal, as well as chain of command issues and a lack of civilian oversight in previous investigations. At the time, Senator Nunn stated, "The Navy's whole investigative technique should be under serious question." As a result of the investigation into the Tailhook scandal, the Pentagon's inspector general was sharply critical of NIS leadership, stating that there was a top-down culture showing a lack of cooperation with other authorities in the Navy. By 1992, Acting Secretary of the Navy, Sean O'Keefe, recommended the word "Criminal" be included in NIS's name in order to make clear their investigative function. Ultimately, NIS commander, Rear Adm. Duvall Williams Jr., was forced to retire and NIS was reorganized as NCIS under civilian leadership.
