The 26-year-old US man accused in the killing of UnitedHealthcare CEO Brian Thompson appeared in a Manhattan courtroom on Thursday to face new federal charges of stalking and murder, which could bring the death penalty if convicted.

Luigi M. is already facing state murder and terrorism charges brought by New York prosecutors, for which, if convicted, he faces life in prison without parole.

He was arrested in Pennsylvania on Dec. 9 after a five-day manhunt.

The suspect was extradited to New York earlier under heavy police escort, overseen by Mayor Eric Adams.

Shackled at the ankles, the accused said little during the 15-minute proceeding in the packed federal courtroom, nodding on being informed of his rights and charges, occasionally speaking to a microphone to tell the magistrate judge he understood.

'Suspect meticulously planned attack'

Luigi M. was arrested in Pennsylvania following a nationwide search for the healthcare executive's killer, a case that captivated America.

At the time of his arrest, prosecutors said he was carrying the gun used to kill Thompson, a passport, fake IDs and some money.

Federal prosecutors allege Luigi M. meticulously planned the attack. The federal complaint said he also had a notebook containing handwritten pages voicing hostility toward the health insurance industry and wealthy executives.

UnitedHealthcare, the largest health insurer in the US, said Luigi M. was never a client.

His New York defense lawyer, Karen Friedman Agnifilo, said he was "overcharged" and vowed to fight the charges in court.

'Luigi freed us'

Outside the Manhattan courthouse, a small crowd of supporters stood waving signs that condemned the health insurance industry.

Among the posters some read "Health over wealth" and "Luigi freed us."

The case has fascinated the American public as Thompson's murder has sparked debate over healthcare practices in the US.

It has exposed people's anger toward the healthcare industry, in a country where some 500,000 people file for personal bankruptcy each year due to medical debt.

*Editor's note: DW follows the German press code, which stresses the importance of protecting the privacy of suspected criminals or victims and obliges us to refrain from revealing full names in such cases. 

ss/lo (AP, AFP, Reuters)