NEW YORK (AP) — A gun and notebook that prosecutors say link Luigi Mangione to the killing of UnitedHealthcare CEO Brian Thompson can be used as evidence at his murder trial, a judge ruled Monday, rejecting a defense argument that they were seized illegally.

Judge Gregory Carro's decision, five months after he held a hearing to examine how police came upon the items, is a major win for prosecutors, enabling them to show jurors a possible murder weapon and motive. That mirrors an earlier ruling in Mangione's federal case.

But Carro also excluded items officers pulled from Mangione's backpack before his arrest at a McDonald's restaurant in Altoona, Pennsylvania. He said the loaded gun magazine, cellphone, passport, wallet and computer chip resulted from an "improper warrantless search." He also excluded some statements he made to police before he was handcuffed.

The judge did allow items found as officers inventoried the backpack's contents later at a police station — including a 3D-printed pistol prosecutors say matches the one used to kill Thompson, and a notebook that describes wanting to "wack" a health insurance executive. Carro said such inventory searches are an exception to the U.S. Constitution's protections against unreasonable searches and seizures. Police obtained a search warrant hours later.

Mangione was arrested on Dec. 9, 2024, five days after Thompson was killed outside a Manhattan hotel. Altoona is about 230 miles (370 kilometers) west of Manhattan.

Mangione, 28, didn't speak as Carro summarized his decision. About two dozen of his supporters, some wearing "Free Luigi" T-shirts, crowded the courtroom's gallery.

Mangione's state murder trial is set to begin on Sept. 8, and his federal trial, which involves stalking charges, on Oct. 13. The federal judge ruled all of backpack's contents into evidence.

Mangione has pleaded not guilty to all the charges, and could spend his life in prison if convicted in either case.

Both sides win something in this ruling

Mangione's lawyers argued that the searches were illegal because officers had no warrant when they looked through the backpack.

Prosecutors argued that the initial search at the McDonald's was legal because it was conducted in conjunction with an arrest and because officers followed Altoona police protocols requiring them to check for dangerous items. But Carro said New York law applies, and that officers had eliminated the justification for an immediate safety search by moving the backpack outside Mangione's "grabbable area" as other restaurant customers passed nearby.

READ MORE: Luigi Mangione speaks out in protest as judge sets state murder trial for June 8

Citing body-worn camera video, Carro also ruled out some statements Mangione made when he was effectively in custody but not yet apprised of his right to remain silent.

Mangione told police early on he didn't want to talk, but officers engaged him for almost 20 minutes before getting him to admit that he had given them a fake name and phony New Jersey driver's license. An NYPD lieutenant testified in December that the shooter had used the same name — Mark Rosario — to buy a bus ticket to New York and stay at a Manhattan hostel.

Surveillance video showed a masked gunman shooting Thompson from behind on Dec. 4, 2024, as the executive walked to his company's annual investor conference. Police say "delay," "deny" and "depose" were written on the ammunition, mimicking a phrase used to describe how insurers avoid paying claims.

Officer's decision to pause search may have tilted ruling

Mangione was not yet under arrest, let alone subject to a judicial search warrant, when officers initially responded to a 911 call about a man who looked like the suspect in Thompson's killing. They began searching his backpack, but stopped after finding the gun magazine wrapped in a pair of underwear. They also found the notebook, Carro noted, but did not open it or see the writings at that point.

"It's him, dude. It's him, 100%," Altoona Police Officer Stephen Fox said on body-worn camera video before telling his colleague to pause the search and resume at the station. "Let's just take it back," he said.

That momentary decision likely preserved the prosecution's ability to use the gun and notebook as evidence at trial. Carro said evidence logged in the subsequent inventory search, including apparent to-do lists and getaway plans, is admissible.

Prosecutors have quoted extensively from Mangione's handwritten diary in court filings, noting his praise for Unabomber Ted Kaczynski and his musings about rebelling against "the deadly, greed fueled health insurance cartel."