He said Mr. Mangione will plead not guilty to the charges he faces in Pennsylvania, including gun charges.
In New York, he has been charged with second-degree murder in connection with Mr. Thompson’s killing, but it is not clear how he will plead. He is currently incarcerated in a Pennsylvania state prison fighting extradition to face murder charges. The legal battle over his extradition could potentially take more than a month to be resolved, officials said.
But legal experts told the BBC that his efforts to extradite him to New York were unlikely to succeed. But they can provide his defense with a glimpse into the state’s evidence against him.
“I don’t even know if this is him,” Thompson’s lawyer Dickey said in a recent interview with American media outlet NewsNation, referring to a photo of Thompson’s killer.
“We will test these circumstances and give the government an opportunity to present evidence,” he said.
If he is extradited to New York to face murder charges, New York lawyer and former prosecutor Mitchell Effner told the BBC there are broadly two approaches Mangione could take if he pleads not guilty.
He said, “Defense number 1 is ‘It wasn’t me,’ and defense number 2 is ‘It was me, but I shouldn’t be punished’ because of X.”
According to New York police, Mr. Mangione was found with a gun similar to the murder weapon, a silencer, fake identification and three handwritten pages hinting at a potential motive.
Mr Epner said the publicly known evidence so far meant denying liability was “out the window”.
Another New York-based lawyer and criminal defense attorney, Professor Dmitriy Shakhnevich, said Mr. Mangione’s lawyers could, in theory, argue that he was unfit to stand trial because of his impaired “mental state.”
“If the judge determines that he misunderstood or did not understand what was happening in the courtroom, essentially the case would not proceed,” he said.
“He will be institutionalized for a period of time until they are deemed fit, but that may never be the case.”
Mr. Shaknevich added that this defense is different from claiming insanity, where his lawyers could argue that “he is not responsible for his actions because of a mental defect.”
“The person may be deemed not guilty because they will not meet the elements of the crime,” he said. “But then again he will not be released. He will be institutionalized for a period of time, assuming the defense is successful.”
