Police are investigating multiple leads in the deadly shooting of Trump ally Charlie Kirk in Utah after the FBI released two photos of a"person of interest".
The images show a person wearing a black baseball cap, black long-sleeved shirt, black trousers and sunglasses.
FBI officials in the Salt Lake City office also announced a $100,000 (£73,000) reward in exchange for information leading to the identification of the attacker.
Follow the latest updates on Charlie Kirk's killing
Earlier, authorities said the sniper was thought to have jumped off a roof and fled into a neighbourhood after firing one shot.
They also said the suspect was a male who"appears to be of college age" and blended in on the Utah Valley University campus in Orem where Mr Kirk was killed.
Mr Kirk, a 31-year-old right-wing influencer, was fatally shot in the neck on Wednesday afternoon while speaking to university students at an event. He died in hospital after being shot.
The rifle suspected of being used in the shooting has been found.
In a briefing on Thursday, FBI agent Robert Bohls said:"I can tell you that we have recovered what we believe is the weapon that was used in yesterday's shooting... is a high-powered bolt action rifle.
"That rifle was recovered in a wooded area where the shooter had fled. The FBI laboratory will be analysing this weapon."
Investigators have collected a footwear impression, a palm print, and forearm imprints for analysis.
The father-of-two was the chief executive and co-founder of Turning Point USA, a prominent organisation that engages conservative youth on school campuses.
He had millions of followers across social media.
Mr Kirk and Turning Point USA played a key role in driving youth support for Mr Trump in last November's presidential election. His events at college campuses nationwide typically drew large crowds.
Many people listened both in person and online to Mr Kirk, as he advocated for conservatism among younger generations and became a leading voice in the Make America Great Again (MAGA) movement.
President Donald Trump paid tribute to Mr Kirk while on stage at a 9/11 memorial event in Virginia, saying he would be awarding him the Presidential Medal of Freedom.
"Before we begin, let me express the horror and grief so many Americans at the heinous assassination of Charlie Kirk have felt," Mr Trump said.
"Charlie was a giant of his generation, a champion of liberty and an inspiration to millions and millions of people. Our prayers are with his wonderful wife, Erika, and his beautiful children."
He later added the FBI was making "big progress" in finding the shooter and he has "an indication" of the motive, but declined to expand.
