Prosecutors to seek death penalty for Mangione as he heads to court

US federal prosecutors have filed a formal notice seeking the death penalty for Luigi Mangione, the man accused of shooting dead a healthcare boss in New York.

Prosecutors argue in the filing that the 26-year-old killed UnitedHealthcare CEO Brian Thompson "to amplify an ideological message" and spark resistance to the health insurance industry.

The move was made just hours ahead of his plea hearing on four federal charges later on Friday.

Previously, a lawyer for Mr Mangione called the decision to seek the death penalty "barbaric".

Mr Thompson was shot dead outside a hotel on 4 December. Mr Mangione was arrested days later in Pennsylvania after a nationwide manhunt.

He has already pleaded not guilty to state charges and is awaiting trial in a New York prison.

Attorney General Pam Bondi said in April that she had directed federal prosecutors to seek capital punishment in Mr Mangione's case for the "premeditated, cold-blooded assassination".

She added Mr Thompson's murder "was an act of political violence" and it "may have posed grave risk of death to additional persons" nearby.

Mr Mangione's lawyer, Karen Friedman Agnifilo, previously accused the government of "defending the broken, immoral, and murderous healthcare industry", and said her client was caught in a tug-of-war between state and federal prosecutors.

"While claiming to protect against murder, the federal government moves to commit the pre-meditated, state-sponsored murder of Luigi," she added.

Investigators argue that Mr Mangione was motivated to kill Mr Thompson, 50, because of anger with US health insurance companies.

In the capital punishment formal notice, filed on Thursday, prosecutors say Mr Mangione poses a future danger because of his expressed intention to target the healthcare industry and rally support to his cause through violence.

Mr Mangione is facing 11 state criminal counts in New York, including first-degree murder and murder as a crime of terrorism.

If convicted of all the counts, he would face a mandatory sentence of life in prison without the possibility of parole.

But federal prosecutors have also separately charged Mr Mangione for using a firearm to commit murder and interstate stalking resulting in death. These charges make him eligible for the death penalty.

Prosecutors have said the federal and state cases will move forward in parallel with one another.

Mr Thompson was shot in the back by a masked assailant in December as he was walking into a hotel where the company he led was holding an investors' meeting.

A nationwide search led police to Mr Mangione five days later at a McDonald's hundreds of miles away in Altoona, Pennsylvania.

The incident ignited a fraught debate about how the US healthcare system operates.

Some Americans, who pay more for healthcare than people in any other country, expressed anger over what they see as unfair treatment by insurance firms.