Recasts headline and lead, adds detail from ruling in paragraphs 5 and 8, comment in 5

By Jack Queen

NEW YORK, May 18 (Reuters) - Luigi Mangione, accused of killing the CEO of UnitedHealthcare, on Monday failed to convince a New York judge to keep a possible murder weapon out of trial evidence, though prosecutors won't be allowed to introduce some other things found in his backpack.

Mangione, 28, is accused of gunning down health insurance executive Brian Thompson on a Manhattan sidewalk in December 2024.

Public officials condemned the brazen killing, but it became emblematic of some Americans’ antipathy for health insurance industry practices and rising costs.

Mangione has pleaded not guilty to murder, weapons and forgery charges. His trial is set to begin on September 8 and is expected to last six weeks.

The ruling by Justice Gregory Carro lets prosecutors introduce evidence against Mangione of a possible murder weapon and a notebook with potentially incriminating writings, while giving Mangione a partial win by excluding other evidence.

A spokesman for Manhattan District Attorney Alvin Bragg said prosecutors look forward to presenting their case. A Mangione representative declined to comment.

Carro suppressed some evidence found in Mangione's backpack during his arrest in Pennsylvania, ruling police unlawfully searched the bag without a warrant. That evidence included a loaded handgun magazine, cell phone and computer chip.

The judge nevertheless approved a second search of the backpack at a police station, and said items recovered there are admissible. Those items included a gun that prosecutors say matches the murder weapon and the notebook with writings about wanting to "wack" an insurance executive.

Carro denied Mangione's bid to suppress his initial statements to law enforcement, rejecting his argument that he was illegally interrogated.

The judge announced his decision during a brief hearing at a New York state court in Manhattan, with Mangione in attendance.

ADDITIONAL EVIDENCE

Mangione’s lawyers argued that his backpack contents and statements to law enforcement during his arrest in Pennsylvania were inadmissible because he was illegally searched and not advised of his legal rights.

Prosecutors deny that Mangione was illegally searched and questioned.

In court filings, prosecutors have detailed a broad range of evidence linking Mangione to the killing, including DNA, fingerprints, hundreds of hours of video footage, a cell phone and another backpack that he allegedly dropped during his flight from New York.

Thompson, who led UnitedHealth Group's UNH.N health insurance business, was shot and killed on December 4, 2024, outside the Hilton hotel where the company was holding an investors’ meeting.

Mangione was arrested in Pennsylvania after a five-day manhunt and has been jailed ever since.

State prosecutors initially charged Mangione with terrorism, but Carro threw out that charge after finding there was not enough evidence to show Mangione’s alleged actions were aimed at influencing public policy.

Federal prosecutors with the U.S. Attorney’s Office for the Southern District of New York separately brought murder, weapons and stalking charges against Mangione.

The judge overseeing that case threw out the murder and weapons charges on a legal technicality in January. That eliminated the possibility of the death penalty.

Mangione has pleaded not guilty to the remaining stalking charges and could face life in prison if he is convicted.