The Bucks County man accused of beheading his father bought a gun the day before fatally shooting him, officials say

A day before authorities say he decapitated his father and posted a graphic YouTube video calling for the execution of federal employees, Justin Mohn strode into a Bucks County gun shop and legally purchased the 9mm handgun police say he used to carry out the killing.

“There was nothing legally precluding him from purchasing that gun,” Bucks County District Attorney Jennifer Schorn said during a Friday news conference. In the days before visiting Johnston’s Sporting Goods in Croydon, Mohn, 32, who was unemployed and lived with his parents, had surrendered his medical marijuana card in order to possess the firearm.

“That also shows you the clear state of mind that he was in, having planned what he ultimately carried out,” the prosecutor said. Mohn, she said, had neither a history of diagnosed mental health issues, nor a criminal record.

Local police said they were called regarding the son three times, the first in 2011 when he had an argument in his driveway, in 2019 when he himself complained that a coworker had threatened him, and in 2023 when his employer in Philadelphia called about his behavior, asking for legal advice for terminating his employment.

A former colleague who worked with Mohn in Philadelphia delivering flowers last year said Mohn’s misogynistic comments on the job made them uncomfortable, leading staff members to search online for his writings, where he called for overthrowing the government and a “hypothetical violent revolution” against “traitor older generations.”

“This guy is very weird, making people uncomfortable, and he also has all this writing, but you can’t fire people for that,” said one former coworker, who spoke on the condition they not be named for safety reasons.

Mohn quit about a week or two after the discovery, coworkers said.

An autopsy showed Michael F. Mohn, 68, a longtime federal employee, suffered a fatal gunshot wound to the head before he was decapitated Tuesday evening in the family’s bathroom with a kitchen knife and a machete, Schorn said. The father’s head was found wrapped in plastic in a cooking pot.

Mohn’s mother discovered the nightmarish scene, Schorn said, running to a neighbor’s house for help. In the hours before police were called, officials said Justin Mohn posted a harrowing 14-minute video to YouTube, holding the severed head and reciting a script railing against the federal government and its employees, calling for a “second American Revolution.”

At 9:25 p.m. Tuesday he was arrested in Fort Indiantown Gap, more than 100 miles away from the scene of the alleged crime, while walking around a state National Guard training site with a loaded 9mm SIG Sauer handgun that was missing one round, Schorn said.

Shortly after posting the video, Mohn drove to the National Guard site in his father’s 2009 Toyota Corolla and hopped a barbed wire fence, Schorn said. According to the prosecutor, he told investigators it was “an effort to mobilize the Pa. National Guard to raise arms against the federal government.”

Authorities in Bucks County charged him Wednesday with first-degree murder, abuse of a corpse, possessing an instrument of a crime, and he was being held without bail.

» READ MORE: A Bucks County man is facing murder charges after allegedly decapitating his father, then posting about it on YouTube

His father was a longtime civil engineer with the U.S. Army Corps of Engineers in Philadelphia, serving in the geo-environmental section, the Corps said in a statement, which read:

“We are deeply saddened about the tragic death of our teammate Michael Mohn... Our thoughts and prayers are with the Mohn family and we are focused on supporting our grieving employees at this time.”

In Croydon on Friday, Johnston’s Sporting Good Store — a small shop that sells everything from buck urine to guns to cinnamon candles — was quiet, save for the occasional customer. Workers declined to comment on Justin Mohn’s handgun purchase, except to say he had the paperwork needed to buy a weapon.

Middletown Township Police Chief Joseph Bartorilla described the three prior connections his department had with Justin Mohn: Officers first visited his home in 2011, when Mohn was 19, regarding an argument in his driveway. In 2019, it was the son who called the authorities, reporting that he had been threatened by someone at Progressive Insurance — his former workplace in Colorado Springs, which he unsuccessfully sued for discrimination in his job in a call center for being an “overeducated, overqualified young male.”

Progressive, in court documents, said Mohn was terminated for failing to comply with the company’s code of conduct, including “kicking open our facility doors.”

And in 2023, his employer in Philadelphia called Middletown police, Bartorilla said, expressing concern about Mohn’s behavior at work.

Former coworkers at a Philadelphia flower company said Mohn “came off as pompous,” boasting about being a big musician and author.

The former coworkers, who declined to name the business to protect their privacy, said Mohn made many of the queer and nonbinary staff uncomfortable.

“I didn’t like him from the start,” said one former colleague. “He had very strange mannerisms.”

Another coworker said Mohn fantasized about sleeping with clients whom he’d refer to as “trophy wives.”

Before moving back to his parents’ home, Mohn lived in Colorado for several years. A roommate from 2016 recalled him as “a very odd person,” often ranting about his conspiratorial beliefs about the government, and at one point showing him his writings about a man leading a revolution against the government, “powered by his rap music.”

» READ MORE: What we know about the Bucks County man accused of decapitating his father

Mohn didn’t have many friends, the roommate said, but recalled Mohn’s father visiting once, staying overnight.

“I made a pretty consistent effort to keep a little bit of distance,” said the roommate, who asked to remain anonymous to avoid being harassed. At one point, the roommate said Mohn canceled their apartment’s internet connection without consulting him, and when the roommate reinstated the utility, Mohn called the police.

Another time, the roommate said he arrived home to find that Mohn had punched holes in the apartment’s walls and broken a mirror that belonged to the building. Mohn told his roommate he’d “blacked out” in a fit of rage over dirty dishes.

After that, the roommate told Mohn he wouldn’t be renewing their lease. “We were not on good terms.”

Mohn’s online writings mirrored some of the messaging conveyed in the YouTube video after the beheading — entitled “Mohn’s Militia — A Call to Arms for American Patriots” — which advocated for “all militia and patriots and across the USA to kill federal employees,” and put a bounty on the head of a Philadelphia federal judge. The night of the killing, Schorn said, U.S. Marshals worked to ensure the safety of anyone named in the video.

The video remained online on Mohn’s account, which had only a handful of followers, for around five hours before YouTube removed it. In that time, it amassed more than 5,000 views, which Schorn called “incredibly concerning.”

Outside the family’s home in the quiet Levittown suburb Friday, bouquets of flowers rested near the door, and a floral cross was staked in the yard.

Bartorilla said police met with the family Thursday night, and that “our hearts ache for the Mohn family.”

“It’s the whole community that mourns,” the police chief said.

Schorn said Friday she couldn’t yet speak to whether anything had occurred leading up to the alleged murder.

But for the grieving family, she said, “this is the unimaginable.”

Staff photographer Tyger Williams contributed to this article.