Luigi Mangione, 26, was arrested on Monday and charged in connection with the fatal shooting of UnitedHealthcare CEO Brian Thompson, capping a dayslong manhunt for a person of interest in the shooting.

Mangione was arrested in Altoona, Pennsylvania, after a McDonald’s employee recognized him from photos released by the New York Police Department and called the authorities. He was charged with two felonies and three misdemeanors in Pennsylvania, and New York prosecutors later filed a murder charge against him, as well as additional counts of forgery and illegal weapons possession.

Mangione comes from a wealthy, prominent real estate family in Baltimore that owned country clubs, radio stations and nursing homes in the area, The Baltimore Banner reported. He was well-liked among friends and former classmates, who expressed shock at his arrest.

In a statement released on Monday night through his cousin Nino Mangione, a Maryland state delegate, the family said they are “shocked and devastated” by his arrest, extended “prayers to the family of Brian Thompson” but declined to comment further.

Throughout his life, Mangione attended elite schools, where he excelled. He studied at Gilman School, a private all-boys institution where he was a valedictorian of his graduating class in 2016. He graduated from the University of Pennsylvania in 2020 with a bachelor’s and a master’s degree. He was a member of UPenn’s chapter of Eta Kappa Nu, an honor society for top students in electrical and computer engineering. Mangione also worked as head counselor at a pre-collegiate program at Stanford University in the summer of 2019.

Mangione was an avid gamer. According to The New York Times, Mangione said in a now-deleted interview published on UPenn’s campus events blog in 2018 that he taught himself to code in high school so that he could create computer games. It was why he chose computer science as his major, he said.

He founded UPenn’s first video game development club, according to his LinkedIn. On the platform, he also lists four years of employment as a data engineer at TrueCar, an online marketplace for new and used cars.

Police said that when they arrested Mangione, he was carrying a ghost gun, which can be assembled from parts bought online and can be extremely difficult to trace. NYPD Chief of Detectives Joseph Kenny said the weapon “may have been made on a 3D printer.”

As police and the media continue to dig into Mangione’s background, authorities are still working to identify a motive in Thompson’s shooting.

Mangione’s extensive online trail may offer some clues as to his thinking and his state of mind. He was active on Goodreads, a website where users share reviews and rate books they’ve read. Mangione had a painful back condition that he struggled with, his friends told The Wall Street Journal, and his Goodreads account lists several books about dealing with back pain.

One of the more closely scrutinized reviews on Mangione’s Goodreads account was on Unabomber Ted Kaczynski’s anti-technology manifesto. Mangione called Kaczynski’s actions “those of an extreme political revolutionary” and quoted a take he said he had seen online:

When all other forms of communication fail, violence is necessary to survive. You may not like his methods, but to see things from his perspective, it’s not terrorism, it’s war and revolution. … These companies don’t care about you, or your kids, or your grandkids. They have zero qualms about burning down the planet for a buck, so why should we have any qualms about burning them down to survive?

This is a developing story. Check back for updates.