Ross Prio (born Rosario Prio) (May 20, 1901 - December 14, 1972) was a Chicago mobster and high-ranking member of the Chicago Outfit criminal organization from the 1930s until the early 70s.
Born in Sicily, Prio was brought to the United States by his adoptive parents in 1909. The family eventually settled in Chicago. As a young man, Prio accumulated an extensive arrest record, but a court order expunged it in 1929. During the later years of Prohibition, Prio became involved in bribing politicians and police officials for the Chicago Outfit. Prio made many loans to high-ranking police officials, including at least one member of the Chicago police intelligence unit.
Over time, Prio gained a reputation as one of the Outfit's leading torture and murder specialists. According to one account, Prio's reputation alone persuaded a plaintiff to drop a million-dollar lawsuit against a prominent Chicago politician. Prio was a suspect in several gangland slayings and bombings throughout his criminal career. Prio was a prime suspect in a series of bombings of dairy firms which competed with his own legitimate milk companies.
Although second to Outfit boss Sam Giancana, Prio was consulted on all Outfit murder contracts. However, according to federal wiretaps, mobster Jackie "The Lackey" Cerone was heard warning mobsters to avoid Prio, who was known to be vacationing in the area at the time, as they prepared for the assassination of Giancana in Hollywood, Florida. This specific attempt on Giancana's life was later abandoned, reportedly by Prio himself who had been informed of Cerone's activities.
Appearing before the McClellan Committee during the 1950s, Prio pleaded the Fifth Amendment to the Constitution at least 90 times. During the hearings, Prio claimed to be strictly a businessman with many legitimate businesses. These businesses included cheese and canned whipped topping processors, currency exchanges, office buildings, hotels, motels, nightclubs, restaurants, finance companies, vending machine outfits, attendant services for clubs and hotels and interests in oil wells, real estate, and Las Vegas casinos.
In 1972, Ross Prio died of natural causes. By the time of his death, Prio had reportedly amassed a fortune far greater than that of infamous Outfit boss Al Capone.