Long-hidden items and documents related to the 1963 assassination of President John Kennedy were revealed for the first time after spending nearly two decades inside a court safe.
Dallas County district attorney Craig Watkins presented the articles at a news conference.
The items include a purported transcript between Kennedy assassin Lee Harvey Oswald and Oswald's killer, nightclub owner Jack Ruby; a leather gun holster that held the weapon Ruby used to shoot Oswald; and brass knuckles found on Ruby when he was arrested.
Mr Watkins said investigators told him about the contents of the safe shortly after he took office in 2007. "Every DA [district attorney] up until the new administration decided that they wanted to keep it secret," he said, but he decided "this information was too important to keep secret".
One of the most intriguing items was the typed transcript of an alleged conversation between Oswald and Ruby. The transcript - which has not been examined by experts and has already been called far-fetched by some - includes talk of killing the president at the behest of the Mafia.
Ruby killed Oswald on November 24th, 1963, two days after Oswald was arrested for the assassination of President Kennedy. Ruby was convicted and sentenced to death the following year. Ruby won an appeal of his conviction but died of cancer before he was retried.
The two-page transcript resembles one published by the Warren Commission, which investigated Mr Kennedy's assassination and determined Oswald was the lone gunman.
In the report, the FBI concluded that transcript of an alleged conversation between Oswald and Ruby was fake, and that it had been "recreated" for authorities by a now-dead Dallas lawyer who claimed he recognised Oswald in a newspaper photo as the man he saw talking to Ruby.
The transcript unveiled yesterday is dated October 4th, 1963, and allegedly happened at the Carousel Club, a Dallas nightclub. It begins with a discussion of how the "boys in Chicago" want to "get rid of" US attorney general Robert Kennedy, JFK's brother.
"There is a way to get rid of him without killing him," Oswald says. "How's that?" Ruby responds. "I can shoot his brother," Oswald says. After a discussion of the logistics of shooting the president, Ruby says the money for the operation's coming from the Mafia.
"Are you with the Mafia?" Oswald asked. "You're asking too many questions," Ruby responds. Later, Ruby gives a lengthy warning that Oswald must not get caught or say anything, noting that "if you do talk, then the boys will make me follow you, wherever you go, and kill you".
AP