Luigi Mangione, the 26-year-old accused of murdering UnitedHealthcare CEO Brian Thompson on December 4 in Manhattan, entered a plea of not guilty in a New York State court on Monday.

Mangione faces 11 charges, including first-degree murder, second-degree murder as a crime of terrorism, and several weapons-related offenses. If convicted on the most serious charge, he could receive a sentence of life imprisonment without parole.

The charges against Mangione include one count of first-degree murder, two counts of second-degree murder, two counts of second-degree criminal possession of a weapon, four counts of third-degree criminal possession of a weapon, one count of fourth-degree criminal possession of a weapon, and one count of second-degree criminal possession of a forged instrument, Fox News reports.

Karen Friedman Agnifilo, Mangione’s attorney, expressed concern that statements from public officials, including New York City Mayor Eric Adams, jeopardized her client’s right to a fair trial. “I’m very concerned about my client’s right to a fair trial,” Agnifilo said in court. She also criticized the treatment Mangione received, describing it as “a human ping pong ball” between jurisdictions and calling his police escort “the worst perp walk I’ve ever seen.”

Mangione remains in federal custody while state and federal authorities work out a transfer. His next court date is scheduled for February 21.

As he exited the courthouse flanked by police, Mangione appeared to raise his eyebrows and shake his head in response to reporters’ questions.

Protesters gathered outside the courthouse, chanting “Free Luigi” and holding signs blaming the healthcare system and family courts for their grievances.

Prosecutors allege Mangione traveled to New York to assassinate Thompson, a Minnesota resident attending UnitedHealthcare’s shareholder conference. They claim he used a 3D-printed ghost gun and suppressor to shoot Thompson from behind.