Luigi Mangione, the man accused of killing Brian Thompson, the CEO of UnitedHealthcare, made his first appearance in a New York City courtroom and pleaded not guilty as his attorney expressed concern over how city officials have handled the case.

A crowd of people, many supporters, flocked to a New York City courthouse, where Luigi Mangione pleaded not guilty to charges of first-degree murder and terrorism in the death of UnitedHealthcare CEO Brian Thompson.

The effects of four days in the dreaded Metropolitan Detention Center (MDC) were immediately apparent when Luigi Mangione was led into a 13th floor courtroom in Manhattan Supreme Court on Monday morning.

Luigi Mangione's attorney immediately raised concerns that her client's rights are being violated, alleging the case is being politicized.

Protesters gathered outside Luigi Mangione’s arraignment at the Manhattan Criminal Courthouse on Monday, December 23, where he faced murder and terrorism charges for allegedly killing United Healthcare CEO Brian Thompson earlier this month.