Federal investigators have recovered what they believe is the rifle used to kill conservative activist Charlie Kirk during a campus event in Utah and released photos of a person of interest in the slaying, as the search for the shooter continued.

The FBI on Thursday released two surveillance photos of an individual in sunglasses and a cap and asked for the public’s help in identifying the person, the agency’s Salt Lake City field office said in a post on X. The agency also offered a reward of up to $100,000 for information relating to the killing.

A press briefing by the FBI and the Utah Department of Public Safety scheduled for 2:45 p.m. New York time was postponed due to "rapid developments” in the investigation, the DPS said.