The FBI said it found a weapon believed to be the one used by the shooter of Charlie Kirk in Orem, Utah. The FBI has released a photo of the alleged suspect.

The US flag is at half-staff outside the White House on Wednesday. Charlie Kirk, executive director of the conservative Turning Point USA advocacy group, has died after being shot at an event in Utah. Photo by Kayla Bartkowski/UPI UPI

Sept. 11 (UPI) -- The FBI said it has recovered a weapon believed to be the one used by the shooter of political activist Charlie Kirk.

The shooter is still at large, but the FBI has released a photo of the alleged suspect, asking for the public's help in identifying the person.

A "high-powered bolt action rifle," was found in a wooded area near where the shooting took place, according to Salt Lake City FBI Special Agent Robert Bohls.

The suspect was dressed in black and allegedly shot Kirk from the rooftop of a university building about 200 yards from the outdoor event where Kirk was speaking.

The suspect is believed to be college-aged. Officials are working "around the clock" to locate the person, officials said during a press conference on Thursday.

The shooter arrived on the campus of Utah Valley University at 11:52 a.m. MDT. Authorities have tracked the suspect through stairwells and up to and across the roof from where the person fired the fatal shot, said Utah DPS Commissioner Beau Mason.

He said they have been able to track the movements of the shooter and have "good" video footage of the suspect, Mason said. The video footage will not be released to the public at this time, he said.

Mason said they are using technology to try to identify the person.

"We are confident in our abilities right now, and we would like to move forward in a manner that keeps everyone safe and then moves this process appropriately," Mason said.

The FBI laboratory will analyze the weapon.

Investigators have also collected "footwear impression, a palm print and forearm imprints for analysis," Bohls said.

Two other suspects have been interviewed by police and released. They are no longer considered suspects.

At a 9/11 remembrance ceremony at the Pentagon Thursday, President Donald Trump said he will award Charlie Kirk a posthumous Presidential Medal of Freedom.

The date will be announced, he said, and "I can only guarantee you one thing, we will have a very big crowd, very, very big."

"Before we begin, let me express the horror and grief so many Americans at the heinous assassination of Charlie Kirk have felt. Charlie was a giant of his generation, a champion of liberty and an inspiration to millions and millions of people," he said at the beginning of his speech.

"Our prayers are with his wonderful wife, Erika, and his beautiful children -- fantastic people, they are. We miss him greatly, yet I have no doubt that Charlie's voice and the courage he put into the hearts of countless people, especially young people, will live on."

In a video Wednesday night, Trump blamed the "radical left" for the shooting.

"It's long past time for all Americans and the media to confront the fact that violence and murder are the tragic consequences of demonizing those with whom you disagree, day after day, year after year, in the most hateful and despicable way possible," Trump said, speaking directly to the American people in a four-minute recorded statement shot in the Oval Office.

"For years, those on the radical left have compared wonderful Americans like Charlie to Nazis and the world's worst mass murderers and criminals. This kind of rhetoric is directly responsible for the terrorism that we're seeing in our country today, and it must stop now."

He listed several attacks against conservatives, but didn't mention any against liberals.