PROVO, Utah - Prosecutors aiming to persuade a Utah judge to advance the case against the man charged with killing Charlie Kirk to trial plan to introduce more police video and a recorded statement from the defendant's roommate as the weeklong preliminary hearing resumes Tuesday.

The hearings opened Monday and have so far yielded no major new details yet represented the most extensive display of evidence presented in the prosecution of defendant Tyler Robinson, 23, who faces aggravated murder charges in the killing of Kirk, a supporter of President Donald Trump.

Former Utah Valley University Officer Christopher Bagley told the court he saw the shooting while the conservative activist addressed a campus audience of thousands on Sept. 10. Shortly afterward, Bagley went to a nearby gravel rooftop where it appeared someone had been lying prone with a direct view of Kirk's position, he said.

"It looks like a sniper pad," Bagley told the court.

Robinson has not yet entered a plea, and his attorneys have not addressed his guilt or innocence. They have, however, tried to remove the death penalty from consideration, so far without success.

If prosecutors follow the sequence of an exhibit list they filed earlier this year, they will show a video from the Washington County sheriff's office from Sept. 11 - the day Robinson surrendered - and recorded testimony from Robinson's roommate.

Prosecutors claim Robinson admitted in a note left for his roommate, who was also his romantic partner, that read: "I had the opportunity to take out Charlie Kirk and I'm going to take it."

Robinson also reportedly texted his roommate that he targeted Kirk because he "had enough of his hatred," prosecutors have said.

Prosecutors have also said they plan to present DNA evidence linking Robinson to the suspected murder weapon, autopsy findings, witness statements and video of Kirk's killing. In addition, they are expected to argue the shooting endangered others at Kirk's campus event - an aggravating circumstance that could make the crime punishable by death under Utah law.

Monday marked the first time Kirk's parents, Kathryn and Robert, and widow, Erika, were in the courtroom since the case began.

Robinson's parents also were present, sitting a few rows behind the Kirks. Robinson sat quietly between his attorneys throughout the hearing, looking at the prosecution's exhibits on a monitor and occasionally taking notes. His wrists were shackled to a chain around his waist.

Prosecutors showed several graphic videos of Kirk's shooting, including of the moment he was shot and security administering first aid, as they made their case to state District Judge Tony Graf.

Kirk's family briefly walked out of the courtroom twice - when Bagley started testifying about Charlie Kirk's arrival on campus and again when prosecutors introduced the videos. Each time, they returned.

The proceeding resembles a minitrial, but prosecutors need only demonstrate that there are reasonable grounds to believe Robinson killed Kirk and should stand trial. The standard is lower than for a trial, where prosecutors must prove guilt "beyond a reasonable doubt."

Prosecutors, as a result, should have little trouble advancing their case, said Mark Kouris, a former prosecutor and state judge in Salt Lake City.

"This standard is extremely low and the chances of them not getting through it are, quite frankly, almost nothing," said Kouris, now an adjunct professor at the University of Utah's S.J. Quinney College of Law.

Defense attorney Kathryn Nester repeatedly objected to evidence introduced by prosecutors. She was mostly overruled by the judge.

When she asked Bagley about finding an empty pistol holster on the ground after the crowd fled, he acknowledged he never took custody of the holster and did not know whether it had been fingerprinted.

Utah is an open carry state, meaning people can carry guns openly or conceal them without a permit.

Graf sided with the defense to block the introduction of a compilation of surveillance videos from Utah Valley University because some had been altered to zoom in or had circles drawn around individuals. Prosecutors said they would try again Tuesday to introduce that video with the alterations removed.

Before his death, Kirk and the organization he co-founded, Turning Point USA, galvanized the conservative youth vote to help Trump win a second term.

The Republican president has said he hopes Robinson receives the death penalty.

Erika Kirk said during her husband's memorial service that she forgives Robinson.

Ahead of Monday's hearing, she thanked supporters in a statement for their kindness and prayers.

"Every court proceeding serves as a painful reminder of his death," she wrote, "and the loss that has irrevocably impacted our lives and the lives of his children."

Brown reported from Billings, Montana.