LOS ANGELES (NPR) -- Lawyers representing convicted assassin Sirhan Sirhan argue in newly filed court documents that a bullet was switched in evidence at his trial and new forensic details show he is innocent of the 1968 killing of Sen. Robert F. Kennedy.
In the latest of many appeals filed on behalf of Sirhan, the attorneys are seeking to overturn his conviction. They repeated a previous assertion and presented reports from experts who said Sirhan was programmed through hypnosis to fire shots as a diversion for the real killer.
Prosecutors had no comment, said Lynda Gledhill, a spokeswoman for the California attorney general's office, which is handling the appeal.
The lawyers, William F. Pepper and Laurie Dusek, also said sophisticated audio tests recently conducted on recordings from the assassination night show 13 shots from multiple guns were fired five more than Sirhan could have fired from his small pistol.
Authorities have claimed eight bullets were fired, with three hitting Kennedy and the rest flying wildly around the kitchen and striking five other victims who survived.
Paul Schrade, who was struck by gunfire, refused to comment on the new filing, saying he is working on his own new analysis of the assassination.
Pepper and Dusek argue that before Sirhan's trial, someone switched a bullet before it was placed in evidence because the bullet taken from Kennedy's neck did not match Sirhan's gun. The lawyers suggest a second gun was involved in the assassination, but they do not know who fired it.
Pepper said the new evidence outlined in a 62-page federal court brief filed in Los Angeles is sufficient to prove Sirhan is innocent under the law.
"They put fabricated evidence into court before the judge and jury" Pepper told The Associated Press. "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," The motion was filed last week in federal court in Los Angeles.
Sirhan, now 67, a Palestinian immigrant, was denied parole after a hearing last March where he denied any memory of shooting Kennedy on June 5, 1968, moments after he claimed victory in the California presidential primary.
Parole officials said he doesn't understand the enormity of his crime that changed U.S. history.
Pepper and Dusek are the latest attorneys to take up Sirhan's case after his conviction and argue on his behalf before parole boards and courts. All of his appeals have been turned down. Pepper, who has taken on other unpopular cases including that of Martin Luther King assassin James Earl Ray, stepped in after Sirhan's previous lawyer died.
At trial, Sirhan took the witness stand and said he had killed Kennedy "with 20 years of malice aforethought." He later recanted the confession. Prosecutors introduced in evidence handwritten diaries in which he wrote: "RFK must die."
The latest filing by Pepper and Dusek relies heavily on a report by audio analyst Philip Van Praag who did tests on an audio recording made by a news reporter during the shooting. The expert concluded that 13 shots were fired and that none of the sounds on the recording were echoes or other anomalies.
The report also claims that the sounds of gunfire were not isolated to one spot in the room but came from different directions.
The lawyers also contend that Sirhan did not have adequate assistance of counsel at trial, noting that his chief attorney, Grant Cooper, decided Sirhan was guilty at the outset and never pursued available defenses.
The Sirhan defense team settled on a claim of diminished capacity and never denied that Sirhan was the shooter of Kennedy, the brief noted.
"Defense counsel did not pursue the issue of a possible substitution of another bullet," the brief said.
Acknowledging "the difficulty of retrying a case of this vintage," the lawyers asked that the sentence be set aside and Sirhan set free.
"Petitioner fully understands that he is likely to be deported to Jordan where he would hope to quietly live out the rest of his life with family and friends, but at long last he would, at least, have received long delayed justice," the filing states.
As an alternative, they asked that the judge set an evidentiary hearing to re-examine the case.