A judge said on Wednesday that he would allow prosecutors to play a redacted video of investigators interviewing a former romantic partner of Tyler Robinson, the 23-year-old man accused of assassinating Charlie Kirk on a Utah college campus last year.

The video is set to be played in court on Thursday and will provide the public its first chance to hear from the former partner, Lance Twiggs. It could provide more insight into what happened in the hours after the shooting on Sept. 10, as well as shed light on the attack, which prosecutors have said Mr. Robinson carried out because of Mr. Kirk’s political views.

But the video will be significantly redacted after Judge Tony Graf ordered that about 15 minutes of it be withheld from the public, in part because of concerns about how it might influence future jurors.

The decision to redact the video drew an impassioned rebuke from a lawyer for Mr. Kirk’s widow, Erika Kirk, who has been attending the hearing in Provo, Utah, this week.

“To not be transparent here, to not be open, to not let the world see what happened, will create doubt and distrust in the judicial system,” the lawyer, Jeffrey Neiman, told the judge.

Mr. Robinson has yet to enter a plea, and the purpose of this week’s hearing is for Judge Graf to determine whether prosecutors have met their burden to bring Mr. Robinson to trial on an aggravated murder charge, which could carry the death penalty if he were convicted. Judge Graf said he was balancing a variety of factors in choosing to keep portions of the video from the public, but that he would still consider the entire video in making his decision.

The hearing is being livestreamed, though it remained unclear if the judge would allow the stream to capture the video of Mr. Twiggs’s interview, or only the audio. The interview took place in April at the offices of Utah County prosecutors, who are leading the case.

Legal observers expect that prosecutors will meet their burden to try Mr. Robinson, but the preliminary hearing has served as a sort of mini trial in which new evidence has been disclosed and lawyers have revealed portions of their potential trial strategies.

At the time of the shooting, Mr. Robinson was living with Mr. Twiggs, and he texted him several times shortly afterward. In that exchange, Mr. Robinson appeared to admit to killing Mr. Kirk and said that he had “had enough of his hatred,” according to court documents.

The authorities have said that Mr. Robinson acted alone and that Mr. Twiggs has cooperated with the police. He was interviewed twice by law enforcement officials and was given limited immunity for doing so.

While Mr. Robinson wrote in text messages to Mr. Twiggs that “some hate can’t be negotiated out,” according to prosecutors, it remains unclear exactly which of Mr. Kirk’s views Mr. Robinson was referring to.

Mr. Kirk had argued over the years that gender transitions conflict with Christian teachings, and had said that the growing transgender movement was “against our senses” and a “middle finger to God.” When he was shot, Mr. Kirk was speaking at an event at Utah Valley University and was answering a question about shootings carried out by transgender people.

Prosecutors said last year that Mr. Twiggs was a man transitioning to become a woman, but both prosecutors and Mr. Robinson’s lawyers have more recently referred to him as a man in court.

Mr. Twiggs’s lawyer, Joel Kittrell, said in an email that he had “no comment on my client’s personal life.”

He added: “As it relates to the prosecution of Tyler Robinson, my client has cooperated consistently with the investigation.”

The hearing resumes on Thursday at 9 a.m. Mountain time.