Luigi Mangione, the suspect accused of shooting health insurance CEO Brian Thompson in New York, is unlikely to be able to mount an effective legal defense to the charges he faces, according to experts.
Mangione, 26, was arrested in Pennsylvania on Monday after a manhunt that lasted for days in several states and ended at a McDonald's restaurant in the town of Altoona.
New York authorities Say forensic evidence Shell casings link him to the crime scene.
His lawyer, Thomas Dickie, previously told local media that he “has not seen any evidence yet” implicating his client.
He said Mr. Mangione will plead not guilty to the charges he faces in Pennsylvania, including firearms charges.
In New York, he was charged with second-degree murder for Mr. Thompson's killing. The 50-year-old UnitedHealthcare CEO was shot and killed by a masked assailant outside a Manhattan hotel on December 4, in what authorities say was a targeted attack.
Mr. Mangione is currently being held in a Pennsylvania state prison where he is fighting extradition to New York to face that murder charge. Officials said the legal battle over his extradition could take more than a month to resolve.
But legal experts told the BBC that his efforts to challenge his extradition to New York were unlikely to be successful. However, they can provide a glimpse into his defense of the state's evidence against him.
“I don't even know if that's him,” his lawyer Dickey said in a recent interview with US media News Nation, referring to photos of Thompson's killer.
“We will examine these waters and give the government an opportunity to provide some evidence,” he said.
If he is extradited to New York to face a murder charge, Mangione and his legal team will face an uphill battle as they try to defend himself, experts said.
Mitchell Ebner, a New York-based lawyer and former prosecutor, told the BBC that there were, broadly speaking, two approaches Mr Mangione could take if he pleaded not guilty to Mr Thompson's murder.
“The first defense is 'It wasn't me' and the second defense is 'It was me, but I shouldn't have been punished' because of X,” he said.
According to the NYPD, Mr. Mangione was found in possession of a gun similar to the murder weapon, a silencer and a fake ID, as well as three handwritten pages that they believe indicate a possible motive.
Ebner said the evidence known so far means denial of responsibility is “out of the window.”
Mangione's lawyer could also, in theory, argue that a weakened “mental state” makes him incompetent to stand trial, said another New York-based lawyer, criminal defense attorney and professor Dmitry Shahnevich.
“If the judge decides he misunderstands, or doesn't understand, what's going on in court, the case won't move forward,” he said.
“He will be placed in hospital for a period of time until he is deemed fit, which may never happen.”
Shakhnevich added that this defense is different from the insanity plea, where his lawyers can argue that he “is not responsible for his actions due to some mental defect.”
“That might make him not guilty, because you wouldn't meet the elements of the crime,” he said. “But again, he will not be released. He will be institutionalized for a period, assuming the defense is successful.”
The beginning of Mr. Mangione's legal battles prompted anonymous donors to raise thousands of dollars for his defense through online fundraisers.
It comes as some online shared support for the suspect and anger at the health insurance industry. The New York City Police Department also warned that some health care executives were potentially in danger because of a “kill list” posted online after Mr. Thompson's killing.
Many of the viral posts included the names and salaries of other insurance executives, the NYPD said in a bulletin. Wanted photo banners were also posted showing some of the Manhattan executives.
Mr Mangione allegedly had complaints about the wider industry.
The current climate means “the threat of copycats is real,” said Timothy Gallagher, a former FBI agent and managing director of Nardello and Co, a global investigations firm.
“There are people who have grievances and are monitoring the amount of pressure and attention the accused gets,” he said.
Mr Gallagher said there had been an “outpouring of support from the dark corners of the internet” for anti-corporate causes.
“I fear this will fuel subsequent attacks,” he said.