Decades-old documents purportedly linked to the 1963 assassination of President John F. Kennedy, among which a transcript of a conversation between Lee Harvey Oswald and his own killer, have been brought to light from an old safe at the Dallas County district attorney’s office.

The news was first brought by the Dallas Morning News on Sunday. The documents had been sitting in the antiquated safe on the 10th floor of the county courthouse for a long time.

Found among the papers was a transcript of an alleged conversation between Lee Harvey Oswald, the president’s assassin, and Jack Ruby, as they plotted the Nov. 22 shooting. According to the Associated Press, the two talked of killing Kennedy because the Mafia wanted to “get rid of” his brother, Attorney General Robert Kennedy.

Oswald reportedly says in the script: “I can still do it, all I need is my rifle and a tall building; but it will take time, maybe six months to find the right place; but I'll have to have some money to live on while I do the planning.”

Oswald himself was shot two days after Kennedy’s death, by Jack Ruby.

One theory concerning the implausible transcript is that the paper is not authentic and more probably part of a movie that former District Attorney Henry Wade, the now-dead prosecutor in the Ruby trial, was working on. The film was never made.

Also in the safe were letters to and from Wade, letters to Ruby, official records from his trial, a gun holster and clothing that probably belonged to Ruby and Oswald, Dallas District Attorney Craig Watkins said.

The AP adds that the disputed paper resembles one published by the Warren Commission, which investigated Kennedy's assassination and concluded Oswald acted alone.

In that other transcript, Oswald and Ruby allegedly talked about killing Texas Gov. John Connally, who was riding in the car with Kennedy and was wounded in the attack. The FBI determined at the time that the conversation was bogus.

Oswald was shot dead by Ruby on Nov. 24 as he was being transferred by police officers to a county jail. Ruby was arrested immediately after the shooting and died from cancer while awaiting a new trial date in 1967.