DALLAS (Reuters) - A batch of old documents linked to the slaying of President John F. Kennedy has reportedly been unearthed, including a highly suspect transcript of a conversation between assassin Lee Harvey Oswald and Oswald’s killer Jack Ruby, the Dallas Morning News said on Sunday.

President John F. Kennedy is seen working in the Oval Office in the White House in this 1963 photo by White House photographer Robert Knudsen provided by the John F. Kennedy Presidential Library in Boston. A batch of old documents linked to the slaying of Kennedy has reportedly been unearthed, including a highly suspect transcript of a conversation between assassin Lee Harvey Oswald and Oswald's killer Jack Ruby, the Dallas Morning News said on Sunday. REUTERS/JFK Presidential Library/The White House/Robert Knudsen/Handout JRB/GAC

The newspaper said the Dallas County district attorney’s office, which uncovered the documents, would display its discovery at a news conference on Monday morning.

The Morning News said the items found in an old safe in a Dallas courthouse included personal letters from former District Attorney Henry Wade, the prosecutor in the Ruby trial. Ruby shot Oswald two days after the president’s death.

Also found were official records from Ruby’s trial, a gun holster and clothing that probably belonged to Ruby and Oswald, District Attorney Craig Watkins told the newspaper.

But one potentially controversial item is a transcript of an exchange between Oswald and Ruby in which they discuss killing Kennedy to halt the mafia-busting agenda of his brother, Attorney General Robert Kennedy.

The Morning News said one theory about the transcript was that it was part of a movie script Wade was working on with producers, for a film that was never made.

The transcript resembles one published by the Warren Commission, which investigated Kennedy’s assassination and concluded Oswald acted alone. The FBI had determined the conversation between Oswald and Ruby -- this time about killing Texas Gov. John Connally -- was definitely fake, the newspaper said.

Connally was riding in the car with Kennedy and was wounded in the attack.

The documents may be a Presidents’ Day gift to conspiracy theorists who have long questioned the official U.S. government version that Oswald acted alone when he shot Kennedy on November 22, 1963, as the president’s motorcade swept past the Texas School Book Depository in downtown Dallas.

Nightclub owner Ruby subsequently shot Oswald dead at point-blank range as police were escorting their prime suspect. Ruby died a few years later from cancer.