Luigi Mangione returned to court Monday for the first day of a pretrial hearing seeking to block prosecutors from using evidence linking him to the December 2024 killing of UnitedHealthcare CEO Brian Thompson.

Prosecutors played surveillance videos of the shooting and Mangione’s arrest at a Pennsylvania McDonald’s, where staff reported him to police after comparing him to released suspect photos.

The defense argued that evidence, including a handgun and a notebook found in Mangione’s backpack, should be excluded because police searched it without a warrant, and they also want to suppress statements made before he was read his Miranda rights, AP has reported.

Mangione, an Ivy League-educated member of a wealthy family, has pleaded not guilty to state and federal murder charges, with state charges carrying life in prison and federal prosecutors seeking the death penalty.

More witnesses are expected on Tuesday, and the hearing could last over a week.