The authorities are still searching for the person who shot and killed the influential right-wing activist Charlie Kirk yesterday in Utah. Check here for the latest updates.

Investigators said they were able to track the gunman’s movements as he climbed onto a roof at Utah Valley University from which he fired a single shot at Kirk, killing him. After the shooting, officials said, the man fled to a nearby neighborhood.

The F.B.I. today released two images of the individual they are searching for, asking for the public’s help, and offered a reward of up to $100,000 for information leading to the arrest of the shooter.

The grainy pictures showed a man in a stairwell wearing a black shirt, a baseball cap and dark sunglasses. Officials said the person “blended in well” at the campus because he appeared “to be of college age.”

State and federal officials also said they had found a bolt-action rifle used in the attack in a wooded area near the site of the shooting. The weapon and several recovered cartridges are being traced by federal analysts. The F.B.I. director, Kash Patel, and his deputy, Dan Bongino, are traveling to Utah to more directly oversee the manhunt.