LEVITTOWN, Pa. — The man accused of killing his father and displaying his decapitated head in a macabre YouTube video has long been obsessed with conspiracy theories, say those who knew him. 

Justin Mohn, 32, was arrested on charges of first-degree murder and other counts after his father, Michael Mohn, was found beheaded in their family home in Middletown Township’s Levittown section Tuesday evening, court records show. 

In a video that was removed by YouTube hours after it was posted Tuesday, the younger Mohn described his father as a federal employee of 20 years and referred to him as a traitor to his country. He also called for the death of all federal officials while allegedly displaying his father’s head.

“We’re all just in shock right now,” John Prickett, 68, who lives down the block from the Mohn residence, said Wednesday.

Michael Prickett, Prickett’s son, was childhood friends with Mohn and remembered him as a “great kid” whom he played hockey with around the neighborhood. He said Mohn was a quiet honor roll student but changed after high school.

“We were pretty close growing up as kids, but once he went to college, he went off the rails,” Michael Prickett, who lives in Trevose, Pennsylvania, said Wednesday. 

“He’s been ranting and railing about the government for 10 years now and how they’re out to get him and how he should be president — all the crazy stuff that was said on the video last night,” Michael Prickett said over the phone. “He’s been essentially doing that for 10 years now.”

Davis Rebhan lived with Mohn in Colorado Springs, Colorado, in 2016, two years after Mohn graduated from Pennsylvania State University, according to a court filing. Rebhan wasn’t close with Mohn, who he said had a reputation for telling tall tales — “like how he got into this big fight with six guys and won.” He also said Mohn “would talk a lot about his beliefs, which were pretty out there.”

“It was a lot of the conspiracy stuff,” said Rebhan, who was a college senior at the time. “He didn’t really have a lot of friends.”

Rebhan, who now lives near Portland, Oregon, said the living arrangement was cordial until one day several months into their lease, when he returned home after a few hours to find Mohn had “caused a significant amount of damage” to their place.

“He broke a big, old mirror that was in our kitchen that had been put up by the apartment, and there were holes in the walls,” Rebhan said. “He basically told me he blacked out and had an incident.”

Mohn never had any friends over at their apartment, Rebhan said. In fact, the only visitor he ever welcomed was his dad one time.

Strange writings

Rebhan had other bizarre interactions with Mohn, including one time when Mohn gave him a copy of a book he had written. 

“It’s about him, but it’s not his name” in the book, Rebhan said. “He is a high schooler who turns into a rap star who leads a revolution against the United States government.”

The book was one of seven self-published books that Mohn had on his Amazon storefront; the books were removed from the platform after news of the alleged murder broke. The writings had dystopian themes and referred to the “second American revolution.” One book, titled “The Revolution Leader’s Survival Guide,” includes the transcript of a letter to then-President Donald Trump warning of “a peaceful revolution helped by the author if positive change does not come to America and the world soon.”

Another book, titled “The Second Messiah: King of Earth,” was “loosely based” on his life, Mohn wrote. It refers to a “four-year stay in Colorado” that “caused multiple lawsuits.”

Mohn also uploaded four original albums to Spotify, where he had five monthly listeners, according to the platform. He used social media to promote his music, which included apocalyptic themes.

Neighbors stunned

The Mohns’ Levittown neighborhood was quiet Wednesday. A resident, Keanya Horton, 46, said she kept her kids home from school because of the police activity overnight. She said that when she saw Mohn’s picture on the news, she immediately recognized him as a man she frequently saw pacing outside.

“The son was kind of crazy. He’d just walk up and down the street, smoking something or sitting on the curb,” she said. “He wasn’t on the phone; he would just be smoking and walking.”

Michael Prickett said Mohn’s father had been a “ very, very good man” who was deeply involved in Mohn’s life growing up. 

“I always remember he and his father having a good relationship,” he said. “He was very supportive of him.”

The U.S. Army Corps of Engineers Philadelphia District said it was “deeply saddened to learn of the tragic death of our teammate Michael Mohn,” who served with the geoenvironmental section.

“Our thoughts and prayers are with the Mohn family and we are focused on supporting our grieving employees at this time,” the district said in a statement.

Prickett said he was stunned when he saw Tuesday night’s YouTube video before it was taken down. 

“I watched the whole video with my mouth wide open. I came to tears over it,” he said. “The kid I remember as a kid was not the kid I saw in the video last night.” 

David K. Li reported from Levittown and Elizabeth Chuck from New York.