Floyd Brown officially pleaded not guilty in Rockford, IL, Wednesday morning to federal charges, including murder.
Brown already faced state charges and is currently being held on a no-bond status. The 39-year-old is accused of killing McHenry County Sheriff's Deputy Jacob Keltner.
Several law enforcement agents and the family of Deputy Keltner packed the courtroom to witness his plea.
Brown appeared in a wheelchair, as he is still recovering from injuries sustained while fleeing from police earlier this month, ABC7 reports.
Authorities said Brown shot Deputy Keltner, who was a sworn member of a U.S Marshals federal fugitive task force, while the deputy was trying to arrest Brown at a Rockford hotel.