Retired Dallas officer Billy Grammer recounts the suspicious phone call that warned of the attack on Lee Harvey Oswald.

Fifty-five years after the assassination of President John F. Kennedy, retired Dallas police officer Billy Grammer recalls a mysterious phone call that warned of the imminent attack on JFK's killer Lee Harvey Oswald.

Speaking with local news station KTBS3, Grammer recalls how after JFK’s assassination on November 22, 1963, he and his unit were working long hours.

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On the evening of November 23, 1963 - the day after JFK’s assassination - Grammer was on night duty as dispatch at the Dallas Police Department.

While on duty, Grammer had a visit from a man familiar to and considered a friend of the Dallas PD, local nightclub owner Jack Ruby.

"He was just like he always was," Grammer says of his meeting Ruby.

The two chatted for an hour over a cup of coffee, but Grammer says Ruby "never once mentioned Oswald." At that point, Oswald was imprisoned at Dallas PD and Ruby was aware of it.

The Dallas PD made it public that they were going to transfer Oswald from their station to county jail by an armored vehicle. However, what they didn’t make public was that the armored vehicle was actually a decoy, and Oswald would be hidden and transported in another vehicle.

After Ruby left the police station following his chat with Officer Grammer, the station received a call from someone who refused to name himself.

“It sounded like Jack Ruby. But I don't know," Grammer says.

"He started telling me about -- if we don't change the plans, we're going to kill Oswald in the basement."

"This guy that called knew about that. And told me about it," said Grammer.

Feeling suspicious about the call, Grammer had a higher-ranking officer listen in and the two typed up a report afterward.

"Chief picked it up and looked at it for maybe 10 seconds," Grammer recalls. "He said, 'Aw, there's nothing to that,' and laid it back down. We said, 'OK,' and walked out."

Grammer acknowledges that the police had been fielding lots of calls regarding both JFK’s assassination and Oswald, but for whatever reason, that one call felt different to him.

"I remember when I got home Sunday morning, I told my wife, 'Somebody's going to kill Oswald in the basement of city hall this morning.' And she kind of laughed about it a little bit."

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Hours later, Grammer’s wife woke him up to deliver the news that Oswald had been shot.

Grammer rushed to the tv to watch the news. "The first person I saw was Jack Ruby. And I thought, 'Oh, me.' I knew this was going to happen."

Jack Ruby's mugshot

Jack Ruby's mugshot

The following day, the police chief said he did not recall receiving Grammer’s tip, even though two other officers backed up Grammer’s story.

“That report has never surfaced," Grammer says. "When all that happened on Sunday and Oswald was killed, I think probably Sunday afternoon the chief probably shredded that thing and threw it in the trash.”

Jack Ruby was arrested for the death of Lee Harvey Oswald. While in prison, Ruby appealed to the Warren Commission, which found that both Oswald and Ruby acted alone, to allow him to go to Washington, D.C. so he could “tell the truth.”

A retired cop recalls a suspicious call he received about the upcoming attempt on Lee Harvey Oswald