Mangione is facing new federal charges in the US that carry the possibility of the death penalty.
Luigi Mangione, the suspect in the murder of UnitedHealthcare executive Brian Thompson, has appeared in a New York court to face new federal charges including murder and stalking.
Mangione was arraigned Thursday after he moved to New York from Pennsylvania after waiving his right to additional proceedings.
Shaking at the ankles and wearing a blue sweater and beige slacks, Mangione said little in a 15-minute appearance before United States Magistrate Judge Katharine Parker in Manhattan.
The 26-year-old Ivy League graduate, who was already facing multiple state charges, was charged with murder with a firearm, two counts of stalking and using a gun silencer illegal, according to an accidental criminal charge.
The federal charges raised the possibility that Mangione could face the death penalty, if prosecutors seek it.
Mangione's attorney, Karen Friedman Agnifilo, said it was an “extremely unusual situation” for a defendant to face state and federal charges at the same time.
“I've honestly never seen anything like what's happening here,” Friedman Agnifilo said.
According to the criminal complaint, Mangione traveled from Georgia to New York “to hunt down and kill Brian Thompson”.
A notebook found in Mangione's possession after his arrest at a McDonald's outlet in Altoona, Pennsylvania contained several handwritten pages that “show hostility toward the health insurance industry and especially wealthy officials”, according to the complaint.
An August entry said “the target is insurance” because it “checks all the boxes,” and an October entry described an intention to “wake up an insurance company CEO,” according to the complaint.
Police say the words “delay,” “deny” and “depose” were scrawled on a shell casing found at the scene of the murder, reminiscent of a phrase commonly used to describe on insurers' tactics to avoid paying claims.
As Mangione was arraigned in court, supporters gathered outside with posters that read “Health over wealth” and “Luigi set us free”.
James Dennehy of the FBI's New York Field Office said Magione's actions amounted to a “carefully premeditated and targeted execution”.
“This alleged plot reflects a more cavalier view of humanity – thinking that murder is an appropriate way to satisfy personal grievances,” said Dennehy.
