The 26-year-old Mangione was arrested at a McDonald’s in Altoona, Pa., on Monday. He faces a gun charge in Pennsylvania but has not been charged in Thompson’s death. A Pennsylvania State Courts spokesperson confirmed Mangione will appear in person at a preliminary arraignment on Monday night in Hollidaysburg, Pa., where he will hear the charges against him.

Officials said Mangione had a “ghost gun” and a three-page manifesto that blasted the health care industry for prioritizing profits over patient care, according to the New York Times. Months earlier, he had read another manifesto.

In January, a Goodreads account with Mangione’s name and photo gave a four-star review to Theodore Kaczynski’s infamous anti-technology critique, Industrial Society and Its Future.

“It’s easy to quickly and thoughtless write this off as the manifesto of a lunatic, in order to avoid facing some of the uncomfortable problems it identifies,” Mangione wrote. “But it’s simply impossible to ignore how prescient many of his predictions about modern society turned out.”

From the 1970s to the 1990s, Kaczynski sent mail bombs around the country that killed three people and injured 23 others, targeting those he believed had pro-technology stances that threatened the environment.

He was arrested in 1996, sentenced to several life terms in 1998, and died in prison in 2023.

Despite Kaczynski’s decades-long string of bombings, Mangione’s review of Industrial Society and Its Future declined to dismiss it as an incoherent rant.

“He was a violent individual—rightfully imprisoned—who maimed innocent people,” he wrote. “While these actions tend to be characterized as those of a crazy luddite, however, they are more accurately seen as those of an extreme political revolutionary.”

Mangione also posted quotes that he called “interesting” from someone else’s Reddit thread about Kaczynski.

That online commenter said Kaczynski recognized “that peaceful protest has gotten us absolutely nowhere and at the end of the day, he’s probably right,” later adding, “When all other forms of communication fail, violence is necessary to survive.”

Like Kaczynski, Mangione is highly educated. He holds a bachelor’s and a master’s degree in engineering and computer and information science from the University of Pennsylvania. He also graduated at the top of his class in high school.

A video of Mangione giving a valedictory address in front of an audience of students, faculty, and parents at the prestigious all-boys Gilman School in 2016 shows a speaker with dark curly hair describing chicken sandwich fundraisers, additional recess time, and hope for the future. He wished classmates well as they said goodbye to high school.

“But now, we’re moving on, and just like we’ve done these past few years, exploring the unknown—whether that be attending colleges across the country, traveling the world during gap years, [or] fulfilling military service in foreign countries,” said Mangione. “As we embrace the new, however, we won’t forget the old friendships, values, and the memories from Gilman will always stay with us.”