Luigi Mangione, the suspect accused of murdering UnitedHealthcare CEO Brian Thompson on Dec. 4 in Manhattan, pleaded not guilty in a Manhattan criminal court on Monday morning.

Mangione, 26, was arraigned on 11 state charges, including murder in the first degree, murder in the second degree as a crime of terrorism, and multiple weapons charges. If convicted on the most serious charge, he could face up to life in prison without parole.

Luigi Mangione enters the courtroom in New York City Criminal Court on Monday, December 23, 2024. Magnione is being arraigned on state charges for the alleged murder of UnitedHealthcare CEO Brian Thompson earlier this month. (Rashid Umar Abassi for Fox News Digital)

The charges include one count of murder in the first degree, a class A-I felony; two counts of murder in the second degree, a class A-I felony; two counts of criminal possession of a weapon in the second degree, a class C felony; four counts of criminal possession of a weapon in the third degree, a class D felony; one count of criminal possession of a weapon in the fourth degree, a class E felony; and one count of criminal possession of a forged instrument in the second degree, a class D felony.

This is a breaking news story; check back for updates.