The suspected assassin of Charlie Kirk was a "very normal young man" who later developed a "leftist ideology" after appearing to become increasingly radicalized in recent years, Utah Gov. Spencer Cox said Sunday.Cox revealed the new details about 22-year-old suspect Tyler Robinson to NBCs "Meet the Press," though said that investigators are not yet ready to discuss a potential motive as they continue to piece together information about the alleged assassin.Cox said family and friends of Robinson described his politics as appearing to shift left after dropping out of Utah State University."It seemed to happen kind of after that after he moved back to the southern part of Utah," he said. "Clearly, there was a lot of gaming going on, friends that have confirmed that there was kind of that deep, dark internet, Reddit culture and these other dark places of the internet where this person was going deep."FBI INVESTIGATING LEFTIST GROUPS FOR POSSIBLE TIES TO CHARLIE KIRKS ASSASSINATION: SOURCERobinson is accused of shooting and killing Kirk as the 31-year-old husband and father of two young children was holding a Turning Point USA event at Utah Valley University on Wednesday."The why behind this, again, we're all drawing lots of conclusions on how someone like this could be radicalized, and I think that those are important questions for us to ask and important questions for us to answer," he said.While Cox did not get into specifics about Robinsons ideology, the governor did point to references engraved on the ammunition used to kill Kirk, with records showing one bullet casing had the message, "Hey, fascist! Catch!""You saw that on the casings," Cox said, noting "the memeification that is happening in our society today."Cox said more information about the suspect and a potential motive may be released Tuesday when charges against Robinson are filed.CHARLIE KIRK'S ALLEGED SHOOTER NOT COOPERATING WITH AUTHORITIES, UTAH GOV. COX SAYSSenior-level FBI officials previouslyconfirmed to Fox News Digital that Robinson was in a "romantic relationship" with a transgender partner. The officials said Robinson lived with the unnamed person, who is a male transitioning to a female and that they shared an apartment in St. George, Utah.Cox said the partner has been "very cooperative with authorities."Robinson, however, has not been cooperating since his arrest, according to Cox."He has not confessed to authorities. He is not cooperating, but all the people around him are cooperating. And I think that's, that's, that's very important," Cox told ABC News.Authorities said Sunday that Robinson is being held under "special watch" pending the completion of a mental health evaluation.Until Robinson clears a mental health evaluation, authorities are keeping a "close eye" on him, theUtah County Sheriff's Departmentsaid in a statement.Fox News Digitals Brooke Singman contributed to this report.