Suspected assassin Luigi Mangione returns to a New York criminal court Friday for a hearing in connection with state murder and terrorism charges in a sprawling case surrounding the assassination-style murder of UnitedHealthcare CEO Brian Thompson in Manhattan.

The 26-year-old former Ivy Leaguer is accused of stalking Thompson, a married father of two, and shooting him in the back outside a shareholder conference in early December, in an alleged attack that investigators have painted as cold-blooded and premeditated.

Many of his defenders have been quick to note he is considered innocent until proven guilty in the eyes of the law. But his significant support is prompting concerns of potential jury nullification — when jurors deliver a verdict based on ideology rather than the law.

“Jury selection is going to be critical in Mangione’s case,” said Edwina Elcox, a Boise-based defense attorney whose former clients have included the so-called “Cult Mom” Lori Vallow. “He is viewed as a modern-day Robin Hood.”

Federal prosecutors allege he stalked the victim, arrived in New York City a week in advance and scouted his surroundings. Police allegedly found his DNA and fingerprints near the crime scene and say he had a gun linked to the murder in his backpack when he was arrested days later.

The NYPD released a still image from surveillance video, showing him pulling his coronavirus mask down and smiling while flirting with a clerk at the check-in of the Manhattan hostel where police say he stayed for the murder. It went viral and immediately attracted a wave of support online for the accused killer.

Luigi Mangione shouts while officers restrain him as he arrives for his extradition hearing at Blair County Courthouse in Hollidaysburg, Pennsylvania on Tuesday, December 10, 2024. (David Dee Delgado for Fox News Digital)

Police said they allegedly recovered the suspected murder weapon, a 3D-printed suppressor and the same fake ID used to check into the New York hostel upon Mangione’s arrest. 

The group behind his defense fundraiser, the self-titled December 4 Legal Committee, describes itself as “a team of 15 volunteers around the United States” that was “created independently by Mangione’s supporters on his behalf.” Two of its spokespersons, Sam Beard and Jamie Peck, also host a podcast “about communism and gossip” called “Party Girls.”

A Monday hearing in the Pennsylvania case has been postponed as he awaits trial on more serious charges in New York and in federal court, which could result in a sentence of life in prison without parole or death, respectively. 

Fox News’ Audrey Conklin contributed to this report.