Tyler Robinson, the 22-year-old man accused of killing Charlie Kirk, lived with a “romantic partner” who has been cooperating with authorities investigating the case, according to Utah Governor Spencer Cox.

Kirk, a prominent right-wing influencer, was shot and killed while speaking at a Turning Point USA rally at Utah Valley University on Wednesday, Sept. 10.

The assassination sparked a manhunt that ended when Robinson was arrested in Washington County, Utah, more than 250 miles from Utah Valley’s campus in Orem.

Authorities said a family member turned Robinson in to authorities after the FBI released surveillance images of a suspected shooter.

Speaking to NBC’s Meet the Press, Cox said that at the time of Robinson’s arrest, he was living with a roommate, whom the governor described as a romantic partner, in St. George, Utah.

Cox said the partner, who has not been identified by authorities, is in the process of transitioning from male to female and helped investigators.

“That person has been very cooperative with authorities,” Cox said.

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When Robinson’s arrest was first announced, Cox said at a press conference that Robinson’s roommate had no knowledge of the crime and provided investigators with Discord messages allegedly sent by Robinson, which authorities claimed discussed details related to the shooting.

Authorities are still attempting to pin down a motive for the killing.

Robinson has not been formally charged, though charges are expected to be filed on Tuesday, Sept. 15. He is currently being held on suspicion of murder.