Jack Ruby was from Chicago, but was no strongman, that is what Pat Manno was for. Ruby was a pimp and was getting ready to make a move to Fort Worth, Texas after he left the Army, there was no Air Force at the time, but he was an aviation mechanic. Fort Worth was the Red light capital of Texas at the time, but city changed made him forget about it. He showed up in Dallas in 1947 where he operated as a nightclub owner and pimp. Sometime in 1949 he met Vincent D'Ingianni a fellow pimp living in Houston who got Ruby involved with arms trafficking. There is enough evidence and statements from Vice Detectives that shows Jack Ruby visiting the Smiling Restaurants that Vincent owned about half a dozen times a year, and informants that said Ruby helped D'Ingianni run guns to Cuba on boats in the early 1950's which led Jack meeting members of New Orleans and Tampa Bay. It is most likely D'Ingianni also got Ruby involved with narcotics. In 1950 he met became friends with Lewis McWillis who worked for Benny Binion while Binion was in Dallas. McWillis would go on to run Casinos in Cuba and later in life worked at the Horseshoe in Las Vegas. On the JFK and Oswalt there are a few threads on here you can look up.