The shooter who assassinated conservative activist Charlie Kirk and then vanished off a roof and into the woods remained at large more than 24 hours later Thursday as federal investigators appealed for the public's help by releasing photos of the person they believe is responsible.

Investigators obtained clues, including a palm print, a shoe impression and a high-powered hunting rifle found in a wooded area along the path the shooter fled. But they had yet to name a suspect or cite a motive in the killing they were treating as the latest act of political violence to convulse the United States across the ideological spectrum.

The photos of a person in a hat, sunglasses and a long-sleeve black shirt, with a backpack, as well as a $100,000 reward for information leading to an arrest suggested that law enforcement thought tips from the public might be needed to crack the case.

Two people who were taken into custody shortly after Wednesday's shooting at Utah Valley University were later released, forcing officials to chase new leads on a separate person of interest they pursued Thursday.

During a news conference Thursday with FBI Director Kash Patel, authorities showed a video of a person being sought in connection with the killing racing across the roof of the building where the shot was fired, dropping down to the ground and fleeing into the woods. In the process, officials say, the shooter left behind imprints, including a palm print, that investigators hope can yield clues to their identity.

Utah Gov. Spencer Cox pleaded for the public's help in the search for the shooter.

Kirk was shot on Wednesday while talking to students at Utah Valley University. A sign posted at the school says the campus is closed until September 15th.