Luigi Mangione has pleaded not guilty in the December 4th shooting death of United Healthcare CEO Brian Thompson. Mangione voiced that not guilty plea to a judge Monday inside a New York City courtroom.

A grinning Luigi Mangione appeared to yuk it up in a Manhattan courtroom Monday as he entered a plea in the murder of UnitedHealthcare CEO Brian Thompson.

"The target is insurance because 'it checks every box,'" read a passage from a notebook, which was dated Aug. 15, that authorities found with Luigi Mangione, according to the court papers.

Luigi Mangione has officially pleaded not guilty after being charged with the murder of UnitedHealthcare CEO Brian Thompson. The 26-year-old entered not guilty pleas on Monday morning, December 23, in New York State court for 11 state counts — including first-degree murder,

Investigators have not uncovered any evidence that Luigi Mangione was insured through UnitedHealthcare, with sources saying the fatal hit was not personal and that the alleged assassin was

Luigi Mangione is set to be arraigned Monday in Manhattan on the state indictment, according to Bragg's office. Here's what else he faces.

Luigi Mangione has been indicted in New York with murder and terrorism in the killing of UnitedHealthcare CEO Brian Thompson. The 11-count indictment filed against Mangione includes one count of 1st-degree murder and two counts of 2nd-degree murder, Manhattan District Attorney Alvin Bragg announced Tuesday.