The Knapp Commission, chaired by New York City attorney William Knapp, was a comprehensive investigation of corruption in the NYPD circa 1971. Published in book form in 1973, the commission's conclusions were controversial. One of the primary witnesses was former beat cop William Phillips. He admitted to regularly accepting graft throughout his fourteen year tenure on the police force. Phillips became the Joe Valachi of the New York Police Department. During Phillips' testimony, a policeman outside had a sign that hung from around his neck. It explicitly accused the Knapp Commission of conducting a witch hunt that reminded some of the restrictive era of McCarthyism in the 1950s.