Michael Paine was born in 1928. After university he worked as a research engineer. In 1958 he began work for Bell Helicopter Company in Fort Worth under Walter Dornberger. After his marriage to Ruth Paine he settled in Irving, Texas. The couple were both active members of the American Civil Liberties Union.
In 1963 Michael Paine left the family home and moved into an apartment in Grand Prairie. According to the author Jim Bishop (The Day Kennedy Was Shot), it was a "friendly estrangement".
Ruth Paine continued to live in Irving and at a party in February, 1963 she was introduced to Marina Oswald and Lee Harvey Oswald by George De Mohrenschildt. On 24th April, 1963, Marina and her daughter went to live with Ruth Paine. Oswald rented a room in Dallas but stored some of his possessions in Ruth Paines garage. Ruth also helped Oswald to get a job at the Texas School Book Depository.
According to fellow worker, Dave Noel, Michael Paine discussed the "character of assassins" a few hours before President John F. Kennedy was killed. He also returned to his home in Irving at 3.00 p.m. to find Dallas police officers searching the premises. He told the police: "As soon as I found out about it, I hurried over to see if I could help."
Anthony Summers reported in his book, The Kennedy Conspiracy that Michael Paine was overheard talking to his wife on the phone. He said that he was sure that Lee Harvey Oswald had killed John F. Kennedy. He added: "We both know who is responsible."
Buddy Walthers took part in the search of the home of Michael Paine. Walthers told Eric Tagg that they "found six or seven metal filing cabinets full of letters, maps, records and index cards with names of pro-Castro sympathizers." James DiEugenio has argued that this "cinches the case that the Paines were domestic surveillance agents in the Cold War against communism."
A work friend of Michael Paine, Frank Krystinik, told the Warren Commission about how he reacted when he heard the news that J. D. Tippit had been killed: "We heard that Officer Tippit had been shot, and it wasn't very long after that that it came through that the Oswald fellow had been captured, had had a pistol with him, and Michael used some expression, I have forgotten exactly what the expression was, and then he said, "The stupid," something, I have forgotten. It wasn't a complimentary thing. He said, "He is not even supposed to have a gun." And that I can quote, "He is not even supposed to have a gun." Or, "Not even supposed to own a gun," I have forgotten."
Jim Garrison later suggested that Ruth Paine might have been involved in setting Oswald up as the "patsy". Garrison points out that Paine's father " had been employed by the Agency for International Development, regarded by many as a source of cover for the C.I.A. Her brother-in-law was employed by the same agency in the Washington, D.C. area." He also claims that he had tried to "examine the income tax returns of Ruth and Michael Paine, but I was told that they had been classified as secret.... What was so special about this particular family that made the federal government so protective of it?"
In 2002 Thomas Mallon wrote a book about Ruth Paine's involvement in the case, Mrs. Paine's Garage and the Murder of John F. Kennedy. Unlike Jim Garrison Mallon took the view that Paine was completely innocent of any involvement in the Kennedy assassination conspiracy.