The lawyers representing convicted assassin Sirhan Sirhan has said he was framed for the 1968 assassination of Robert F. Kennedy and that they are seeking to overturn his conviction.

They have filed new court documents arguing that a bullet was switched in evidence at his trial and that new forensic details show that Sirhan is innocent of the killing, according to The Christian Science Monitor.

The new evidence was filed in Los Angeles last week and is outlined in a 62-page federal court brief.

The attorneys have repeated assertions from experts claiming Sirhan was programmed through hypnosis to fire diversion shots for the U.S. senator's real killer.

Lawyers William F. Pepper and Laurie Dusek have said that audio tests recently done on recordings from the night Kennedy died prove that 13 shots were fired from multiple guns. That is five more shots than Sirhan could have released from his small pistol, which could only fire eight bullets.

But authorities said only eight were fired, three of which hit Kennedy while five bullets hit others who all survived being shot.

According to the UK's Daily Record, Sirhan's lawyers claim that a bullet taken from Kennedy's neck didn't match their client's gun and that a switched was made before it was placed in evidence. A second gun was involved in the assassination, the lawyers suggested. But they have no clue who pulled that trigger.

They put fabricated evidence into court before the judge and jury Pepper told The Associated Press, as reported by CS Monitor. We are satisfied that for the first time in 43 years of this case we think we have the evidence to set this conviction aside.

Sirhan, a Palestinian immigrant, is now 67 years old. He was denied parole after a hearing last March. Sirhan has also denied any memory of shooting Kennedy on June 5, 1968. Parole officials have also said Sirhan doesn't understand the how huge this crime was, CS Monitor reported.