Cain was never brought up on charges but was forced to resign from the force and left Chicago for awhile to cool off.
Following his return to the windy city he started his own investigations company Accurate Laboratories specializing in investigations, guard / undercover services, polygraphs and wiretapping. It was during this time that the CIA began subcontracting some of it's work to the Chicago mob and Cain returned to Cuba to assist in the Bay of Pigs and later attempts to kill Fidel Castro. He also did work for the Federal Police in Mexico until he beat a man then tried to arrest him. This escapade got him deported back to the states and Chicago.
Back in Chicago returned to work for Richard Ogilvie helping him in his run for Cook County Sheriff. Ogilvie won the election and as a reward Cain was made head of the county's Special Investigation Unit. It was the zenith of his career during that time he allegedly became involved in Kennedy's assassination his mentor Sam Giancana fingered Cain as one of the JFK shooters indeed as the actual gunman in the alleged ‘Oswald sniper’s nest’ in the Texas School Book Depository. Followed by his attempt to take over the Chicago outfit. Culminating with his kidnap Joey Aiuppa who would go on to head the outfit in the 1970's and early 80's.
Cain was becoming a threat to the established order and needed to be taken down a couple of pegs. He had plans to take over as sheriff when he found himself in legal trouble. In December 1963 thieves stole $250,000 worth of prescription drugs from Zahn Drug Company in Melrose Park another bastion of mob power in suburban Chicago. Later some of the drugs were recovered in a raid at the Careville Motel that was led by Cain. As it turned out the raid was staged the motel had been rented by an SIU sergeant that reported directly to Cain. Also Zahn claimed that Cain offered to sell them back the drugs just a few days before the raid. Cain and three others were indited and dismissed from the Sheriffs Department.
Although he still had Sam Giancana as a protector Momo was having his own problems with both the law and the real bosses of the outfit Paul “the waiter” Ricca and Tony Acardo. The heat was so intense that both Giancana and Cain relocated to Mexico in 1966. He would still make trips back to Chicago and during one of these trips FBI agent Bill Rohmer tried to recruit him as an informant. Cain declined and during another Chicago visit got arrested for his connection to a 1964 bank robbery. He was convicted in 1968 and a year later he was finally convicted in the Zahn case.
Richard Cain was imprisoned until 1971 when he was paroled and returned to the streets of Chicago. There he tried working both sides of the street as an on again off again informant for Rohmer while still doing jobs for the mob. He was allegedly one of the gunmen in the assassination of “Mad” Sam DeStefano. Another of his projects was to turn his Bay Of Pigs story into a movie. By late 1973 Cain had several meetings with Marshall Caifano about taking over the south side gambling operations.
He had been talking too much though and not just to Bill Rohmer his loose lips were getting wider. As an expert wiretapper he'd been making tapes in 1973 he said to girlfriend Marlene Kennedy ‘If anything happens to me, listen to this tape. It’s worth a lot of money to you.’ Then on December 19, 1973 ‘Richard Cain let it slip in a bar in the hearing of outsiders that he and his chief had had something to do with an international conspiracy and a political murder on an assignment from the CIA. Exactly 24 hours later two masked men walked into the same bar, ordered everyone at gunpoint to line up face against the wall, singled out Cain, shoved a gun barrel in his mouth and silenced him for good.’ After blowing his head off and before leaving the killers took something off his body.
Michael J. Cain, The Tangled Web, 2007.