Luigi Mangione, the man accused of gunning down UnitedHealthcare chief executive Brian Thompson, will not face the death penalty if convicted, a court has ruled.

US District Judge Margaret Garnett dismissed the federal firearms charges against the 27-year-old that carried the possibility of capital punishment.

He will still face stalking charges, which can bring a maximum sentence of life in prison.

Mangione was arrested days after he allegedly shot Thompson as the health insurance firm CEO walked into a New York City hotel on 4 December 2024. He has pleaded not guilty to all federal and state charges.

After the ruling, Mangione's attorney Karen Agnifilo thanked the court for this incredible decision, according to CBS News. We're all very relieved, she said. We're prepared, and have been prepared, to fight this case, and we look forward to fighting this case.

In her ruling, Garnett, appointed by former US President Joe Biden, stated that two of the four federal charges did not meet the federal statutory definition of a 'crime of violence' as a matter of law. She noted that her decision was solely to foreclose the death penalty as an available punishment to be considered by the jury.

Garnett's ruling was a setback for the justice department, which had called Thompson's murder a premeditated, cold-blooded assassination. The judge has given the government 30 days to challenge her decision to rule out the death penalty in the case.

In a win for prosecutors, Garnett stated that they could present evidence from Mangione's backpack found at the time of his arrest in Pennsylvania. This bag contained a gun, fake IDs, and a notebook with writings allegedly detailing Mangione's grievances against the US healthcare system.

Mangione, an Ivy League graduate from a wealthy Maryland family, faces nine charges in a separate case led by New York state prosecutors, including second-degree murder. Thompson was shot from behind by a masked gunman as he entered a Manhattan hotel for an annual investor conference. Investigators found shell casings near Thompson's body, inscribed with the words deny, defend and depose, believed to reference tactics used by insurance companies to reject payment claims.

Jury selection in the federal trial is set for 8 September, with opening statements commencing on 13 October. However, state prosecutors are eager to try Mangione as soon as July.