The suspect in the shooting of UnitedHealthcare CEO Brian Thompson last week, 26-year-old Luigi Mangione, was thought by his mother to be living in San Francisco earlier this year, though it's not at all clear that he ever did.

Social media has been flooded for the last 24 hours with postings that cast Luigi Mangione as both folk hero and murderer, and with plenty of images of him shirtless and smiling culled from his Instagram and Twitter accounts, which have since gone offline. As CNN reports, friends have known him for years to post images from his travels, and to maintain a mostly positive-seeming social media presence.

That seems to have stopped earlier this year, and by July, friends were posting things publicly like "I haven’t heard from you in months," and "I don’t know if you are okay."

One user also posted to Xitter in October, "Nobody has heard from you in months, and apparently your family is looking for you."

Now we learn, as the Chronicle reports, that Mangione's mother filed a missing persons report with the San Francisco Police Department just a few weeks before the shooting, on November 18. In it she stated that she had last spoke to Mangione in July, and she believed he was working in the city at car-sales startup TrueCar, which is where he was listed on his LinkedIn as being employed.

Kathleen Mangione reportedly told the SFPD she believed he was working at TrueCar at 124 Montgomery Street, which was listed as permanently closed, and it's not clear if TrueCar, which is based in Santa Monica, ever had offices there.

Mangione's mother did not suggest that her son presented any kind of threat, and she reportedly told police she didn't know where he may have frequented in town.

As SFist reported Monday shortly after Mangione's arrest, we know that he had an interest in AI and engineering, and that he had spent a summer in the Bay Area at Stanford in 2019, while he was attending undergrad at UPenn.

He graduated in 2020, and CNN reports that he had been working remotely for TrueCar while living in Honolulu for about six months in 2022. The New York Times reports that, according to TrueCar, he had not been an employee since 2023.

According to his family, Mangione had dropped out of contact sometime after having back surgery around August 2023, and that July contact with his mother is the last we know of. (His last post on his now-removed Instagram account had been photos from the Big Island in Hawaii in 2021.)

A friend who runs a co-living compound in Honolulu for remote workers, RJ Martin, has spoken to both the Times and CNN and said that Mangione was mostly "upbeat," and they had been in touch until earlier this year, but Mangione went silent sometime around March or April. Martin said that Mangione had confided in him about his back issues — a spinal misalignment that caused him a good deal of pain — and said that he said he was not able to be physically intimate with another person without pain.

Martin also said that Mangione's back problems were exacerbated after he took a surfing lesson in Hawaii in 2022, after which Mangione was "in bed for about a week."

After last seeing family in Baltimore sometime last year, it seems like no one is sure where Mangione has been living for the past six to 12 months or more, and many friends have expressed disbelief that he could have undergone any sort of mental break.

Indeed, a brief handwritten note found in his backpack when he was arrested Monday in Altoona, Pennsylvania suggests pretty solid lucidity, and he appeared to take full responsibility for the shooting death of Thompson.

Per the Times, the note reads, "To save you a lengthy investigation, I state plainly that I wasn’t working with anyone... [healthcare companies] continue to abuse our country for immense profit because the American public has allowed them to get away with it," and he noted that during the time UnitedHealthcare’s market capitalization has grown, American life expectancy has not.

While being escorted into an extradition hearing Tuesday, as CBS News reports, Mangione was heard having an outburst before being pinned to a wall by officers in Blair County, Pennsylvania. He reportedly shouted, "This is completely unjust and an insult to the American people!"

Previously: Man Arrested In Connection With Healthcare CEO Slaying Spent Time In Bay Area