A video interview with Robinson's former roommate and romantic partner, Lance Twiggs, was played in court as prosecutors tried to convince a Utah judge they have sufficient evidence against Robinson to warrant a trial.
Robinson, who was studying to be an electrician at the time of the shooting, faces seven criminal charges including aggravated murder. Prosecutors are seeking the death penalty. He has yet to enter a plea.
The 31-year-old Kirk, a prominent ally of President Donald Trump, was killed in front of thousands as he debated students at Utah Valley University. It is one of the highest-profile incidents among a series of attacks on politicians and prominent figures that have intensified concern over US political violence.
In the April 20 interview, which was partially redacted on the orders of District Judge Tony Graf, Utah County prosecutor Ryan McBride asked Twiggs about text messages he exchanged with Robinson in the hours after Kirk was killed on September 10, 2025. In the text messages, Robinson allegedly admitted to Twiggs that he shot Kirk.
Twiggs said Robinson returned to their townhouse in St. George, Utah, on the morning of September 11.
"I just asked him in person if what he said was true the night before, and he said it was. He started crying a little bit and said he wishes he hadn't done it," Twiggs told McBride in the interview.
Twiggs agreed to the interview with prosecutors and police in lieu of testifying at the preliminary hearing, and was granted immunity for his cooperation.
Judge Graf barred parts of the interview from being played in court after Robinson's lawyer said prosecutors would portray the clips as "confessions" and jeopardise the defendant's right to a fair trial.
The court holds the last day of the preliminary hearing on Friday. The prosecution and defence will then submit written arguments before Graf holds a September 1 hearing on the matter.
In court this week, Robinson's lawyers suggested police failed to investigate possible evidence that someone else might have carried out the killing.
Text messages presented by prosecutors show that Twiggs asked Robinson why he shot Kirk, and he replied: "I had enough of his hatred. Some hate can't be negotiated out."
Prosecutors contend the text messages indicate Robinson targeted Kirk because of his conservative political views, including anti-LGBTQ comments. The defence disputes the prosecution's characterisation and has sought to limit the use of evidence pointing to a political motive, which could be used in arguments for the death penalty.
