NEW YORK — A federal judge in New York on Tuesday appointed a death penalty expert to the defense team of Luigi Mangione, the man accused of gunning down UnitedHealthcare CEO Brian Thompson in front of the Hilton in Midtown Manhattan.

One of the federal charges, murder through use of a firearm, makes 26-year-old Mangione eligible for the death penalty if convicted.

Judge Katherine Parker, in a brief order Tuesday, approved the appointment of Avraham Markowitz, an expert in capital cases.

Mangione’s retained counsel, Karen Friedman Agnifilo, is his lead attorney.

“The Agnifilo Intrater team is pleased to have Avi Moskowitz lend his considerable expertise in death penalty cases to Mr. Mangione’s federal case as ‘learned counsel.’ The charges could not be more serious and our client needs every resource at his disposal to fight these unprecedented charges in three jurisdictions,” a spokesperson for the firm said in a statement provided to ABC News.

Mangione pleaded not guilty to the 11 charges in the indictment, including first-degree murder in furtherance of terrorism.

He is also charged in New York with two counts of second-degree murder, one of which is charged as killing as an act of terrorism; two counts of criminal possession of a weapon in the second degree; four counts of criminal possession of a weapon in the third degree; one count of criminal possession of a weapon in the fourth degree; and one count of criminal possession of a forged instrument in the second degree.

He faces a maximum sentence of life in prison without parole if convicted of the state charges.