Investigators are searching for a motive in the assassination of UnitedHealthcare CEO Brian Thompson as murder suspect Luigi Mangione fights his extradition to New York from Pennsylvania, where police detained him at a McDonald’s on Monday.

Mangione’s lawyer denied his client’s involvement in the killing and said he plans to plead not guilty to Pennsylvania charges related to a gun and fake ID police found when they arrested him after being tipped off by customers at the fast-food restaurant in Altoona.

The 26-year-old Ivy League graduate from Maryland – who faces a slew of charges in the two states related to the deadly shooting in Manhattan last week – was denied bail at an extradition hearing Tuesday afternoon at the Blair County Courthouse in Pennsylvania.

As the suspect entered the courthouse, shackled at the hands and feet and wearing an orange prison jumpsuit with DOC emblazoned on the back, he could be heard yelling, in part, “It’s completely out of touch and an insult to the intelligence of the American people. It’s lived experience.”

New York prosecutors charged Mangione with one count of murder, two counts of second-degree criminal possession of a weapon, one count of second-degree possession of a forged document, and one count of third-degree criminal possession of a weapon, online court documents show.

In the charging documents, detective Yousef Demes of the Midtown North Detective Squad outlined evidence that officials say proves Mangione is the person depicted in surveillance video fatally shooting Thompson outside of a Hilton hotel in Midtown Manhattan as Thompson made his way to his company’s annual investor conference. He noted the man seen in surveillance footage from a New York hostel is wearing the same clothing.

After arresting Mangione in the Altoona McDonald’s, police found “a black 3D-printed pistol and a black silencer” that was also 3D printed, according to the criminal complaint. While being taken into custody, Mangione also presented a forged New Jersey ID with the name Mark Rosario listed as his identification, which matched the ID the man at the hostel used, Demes said in the report.

Mangione’s defense attorney Tom Dickey told CNN’s Kaitlan Collins Tuesday night he has not seen any evidence that New York officials “have the right guy.”

Dickey said his client would be pleading not guilty to the charges he faces in Pennsylvania, which are related to the fake ID and gun found when Mangione was searched. He also said he anticipates Mangione would plead not guilty to the murder charge in New York and that it’s “a possibility” he could represent him there.

As police rush to piece together a potential motive and Mangione’s movements leading up to last week’s shooting, the suspect’s friends and family are left wondering how someone with a promising life could have possibly committed such a brazen crime.

Investigators are looking into an insurance claim for a back injury Mangione sustained in July 2023, New York Police Chief of Detectives Joe Kenny told Fox News. Mangione referenced pain from the injury in his writings, Kenny said.

“Some of the writings that he had, he was discussing the difficulty of sustaining that injury,” Kenny said. “So, we’re looking into whether or not the insurance industry either denied a claim from him or didn’t help him out to the fullest extent.”

Because Mangione is fighting extradition, a Pennsylvania court has given him 14 days to file for writ of habeas corpus, and a hearing will be scheduled if he does. Mangione will stay at Huntingdon State Correctional Institution in Pennsylvania. Prosecutors have 30 days to obtain a governor’s warrant, which New York Gov. Kathy Hochul said she will work with prosecutors to sign. Weeks said his office is prepared “to do what’s necessary” to get Mangione back to New York.

Why Magione may be fighting extradition to New York

Because Mangione is fighting extradition to New York, it could take weeks before authorities can bring him to the state for prosecution, according to Karen Agnifilo, a CNN legal analyst and defense attorney.

There could be several reasons why Mangione is fighting his extradition, Agnifilo said. It allows him more time to think about his defense, demand prosecutors present more evidence at his next hearing or try to get bail in Pennsylvania, which is unlikely, said Agnifilo, who previously worked at the Manhattan District Attorney’s Office.

Most criminal defendants facing prosecution on more serious charges in another state waive their right to extradition, but in murder cases like Mangione’s, “there’s no chance he’s going to be let out, so he’s fighting extradition,” she said.

“Eight or nine out of 10 times, defendants waive extradition because they realize this is so perfunctory, it’s so easy, and most of them don’t want to languish in detention in the other state because you don’t even get to fight your case yet,” Agnifilo said.

Judge Dave Consiglio denied bail related to both state dockets, saying Mangione would remain at the Huntingdon State Correctional Institution. After the governor’s warrant is obtained, Agnifilo said it can take up to two months before authorities can bring Mangione back to New York.

Suspect appeared to view targeted killing as a ‘symbolic takedown’

An NYPD intelligence report obtained by CNN Tuesday said the suspect appeared to be driven by anger against the health insurance industry and against “corporate greed” as a whole.

“He appeared to view the targeted killing of the company’s highest-ranking representative as a symbolic takedown and a direct challenge to its alleged corruption and ‘power games,’ asserting in his note he is the ‘first to face it with such brutal honesty,’” according to the NYPD assessment, which was based on Mangione’s “manifesto” and social media.

Along with a three-page handwritten “claim of responsibility” found on Mangione when he was taken into custody, investigators are looking at pages of notes in a spiral notebook that the suspect wrote in, a law enforcement source briefed on the matter told CNN.

It included to-do lists of tasks that needed to be completed to facilitate a killing, as well as notes justifying those plans, the source said. In one notebook passage, Mangione wrote about the Unabomber, who he wrote about in online posts as well.

Mangione was aware UnitedHealthcare was holding an investors’ conference around the time Thompson was shot and killed — and the suspect mentions he will be going to the conference site, NYPD chief detective Kenny said.

In the notebook passage, Mangione concludes that using a bomb against his intended victim “could kill innocents” but shooting would be more targeted, musing what could be better than “to kill the CEO at his own bean counting conference.”

The three-page document did not include specific threats but indicated “ill will towards corporate America,” Kenny said.

CNN’s Steve Almasy, Sara Smart, Gloria Pazmino, Amanda Musa, Celina Tebor, Elizabeth Hartfield, Jordan Valinsky and Kara Scannell contributed to this report.