William "Willie Rat" Dominick Cammisano Sr. (April 26, 1914 – January 26, 1995) was a Kansas City, Missouri, mobster and enforcer for Nicholas Civella's Kansas City crime family.
By 1929, Cammisano had an extensive rap sheet. He had been arrested for carrying a concealed weapon, bootlegging, pistol whipping a robbery victim, running an alcohol still, being AWOL from the U.S. Army, disturbing the peace, and gambling. It was said that he had stolen everything from the wheels off a truck to the rings off a woman’s fingers. Cammisano once served a felony sentence at a federal prison in El Reno, Oklahoma. In the 1940s, he opened a tavern and called it the El Reno Bar, stating that had been the name of his favorite prison (Federal Correctional Institution, El Reno). He is the father and namesake of William Dominick Cammisano Jr. born May 8, 1949 in Kansas City, Missouri. He lived in Winchester, Nevada.
A high-ranking member of Civella's organization, Cammisano was called in 1980 to appear before a U.S. Senate Subcommittee investigating organized crime activity in Kansas City. During the investigation, government witness Fred Harvey Bonadonna described how Cammisano's used strong arm tactics in the River Quay neighborhood redevelopment project to turn the area into a red light district with brothels and other vice. Bonadonna stated that Cammisano murdered his father, a business associate of Cammisano's, for refusing to obtain liquor licenses for mob establishments in River Quay: "Willie [Cammisano] told my father that he would kill me. My father (David) said he'd have to kill him first."