Kirk investigators: "Aghast" transgender roommate may lead to motive

• Each of the six sources familiar with the investigation told Axios that investigators believe Robinson had a romantic relationship with his roommate.

The latest: Utah Gov. Spencer Cox (R) confirmed Sunday on ABC News' "This Week" that Robinson lived with a romantic partner who was undergoing a gender transition.

• Robinson's roommate is cooperating with authorities, Cox said, but Robinson is not and has not confessed to Kirk's killing.

Zoom in: Axios' sources said investigators initially wanted the information about the roommate's gender identity kept quiet because that person is being "extremely cooperative" with authorities.

• The roommate was "aghast" at the slaying when speaking to investigators and shared electronic messages sent by Robinson, one of the sources said.
• "That's what happened? Oh my God, no," the roommate said, according to the source. "Here are all the messages."
• The phone messages indicated a sender listed as "Tyler" had mentioned that after the shooting, he had wrapped his rifle in a towel and stashed it in some bushes near Utah Valley University, where the shooting occurred, Gov. Spencer Cox said Friday during a news conference.
• "Tyler" also told the roommate in writing that the rifle would have to be retrieved, Cox said.

Between the lines: Federal and state law enforcement officials also are examining leftist groups in Utah to see whether they had knowledge of the alleged shooter's plans beforehand, or if they lent material support to him afterward.

• One of those groups eliminated its social media profile after the shooting, Axios has learned.

The motive and political ideology of Robinson, 22, are subjects of intense online debate. Some conservatives have insisted he's an unhinged leftist. Liberals have pushed back by pointing to Robinson's conservative upbringing in Utah.

• In a Daily Mail interview Friday, family matriarch Debbie Robinson said the family supports President Trump's MAGA movement.
• "Most of my family members are Republican, she said. "I don't know any single one who's a Democrat."

Cox said on NBC's "Meet the Press" Sunday that while Robinson comes from a conservative family, "his ideology was very different than his family."

• He said authorities are trying to piece together how Robinson, a high-achieving student and "very normal young man," was radicalized.
• "Clearly there was a lot of gaming going on," he said. "Friends have confirmed that there was kind of that deep, dark internet, the Reddit culture, and these other dark places of the internet where this person was going deep."

Family members have told reporters that Tyler Robinson had become "more political" in recent years, and had expressed interest in Kirk's visit to the Utah Valley campus in Orem, Utah.

• Cox said a Robinson family member had told investigators that the accused shooter recently had a conversation in which someone said Kirk "was spreading hate and was full of hate." But it was unclear from Cox's remarks who actually made that statement.
• LGBTQ activists have criticized media outlets for erroneously reporting in the hours after the shooting that a bullet casing from the scene included a message related to transgender people.

Zoom out: Kirk, who toured college campuses and challenged progressive students to debate him under a tent that said "Prove Me Wrong," was an outspoken opponent of gender-affirming surgeries for minors and transgender athletes competing in women's sports.

What they're saying: "It's pretty clear that Robinson's roommate knew a lot and didn't say anything after the killing, so they're a person of interest officially and are cooperating," a second official said. "We want to keep it that way."

• "What we want to know is if anyone else had knowledge [of the shooting], before or after," that source said.

Editor's note: This story has been updated with comments and additional information from Utah Gov. Spencer Cox.