An alt-right podcaster from Lehigh County who prosecutors say once encouraged his listeners to assassinate lawmakers, lobbyists and “left-wing billionaires” with explosives is facing federal charges for allegedly amassing a cache of more than a dozen unregistered machine guns.

Prosecutors say Joseph Paul Berger, 32, illegally modified many of the firearms found locked in the basement of his parents’ Bethlehem home, turning them into fully automatic weapons capable of firing hundreds of rounds of ammunition at a time. At a court hearing Thursday, they described him as antigovernment, anti-law enforcement and “an extreme danger to the community.”

But his lawyer, Eric E. Winter, accused the government of misconstruing and exaggerating Berger’s inflammatory rhetoric on his podcast and using the gun charges to punish his client for his political views.

“He never incited violence,” Winter told U.S. Magistrate Judge Pamela A. Carlos. “To be very clear, this is political speech. He never took any action on it. He made it clear that this was a prank.”

Berger, a Navy veteran who lives with his parents and works as a certified armorer and machinist, has not been accused of crimes related to any threats made on his show. Instead, he and his father, Joseph Raymond Berger, were arrested earlier this week on charges stemming only from the weapons cache federal agents seized after raiding their house in January 2021.

Yet, the case comes amid twin efforts by the Justice Department to crack down on the proliferation of illegal guns across the U.S. while also stepping up enforcement against domestic extremists in the wake of the Jan. 6 assault on the Capitol.

Groups with ties to white supremacy like the National Justice Party have rallied around the younger Berger, highlighting his case in online posts in which they accuse the Justice Department of a “blatant disregard for basic civil liberties and due process.”

The younger Berger hosted his podcast “Alt-Right Armory,” under the screen name “GlockDoctor1488,” an apparent reference to the “1488″ symbol popular in white supremacist circles. According to the Anti-Defamation League, the 14 is a nod to a 14-word supremacist slogan about securing a future for white children, while the 88 stands for “Heil Hitler,” with “H” being the eighth letter of the alphabet.

Berger’s show is consumed with highly technical discussions of firearms and their operations peppered with provocative references to extremist views.

In its pilot episode, he mused that “a white man with a rifle can be very dangerous to the system indeed if he has the right motivation” and he has since praised on his program Eric Frein, who was sentenced to death in 2017 for the ambush slaying of Pennsylvania State Police Cpl. Bryon K. Dickson.

As for his talk of targeted assassinations of lawmakers and law enforcement, Berger maintains it was a joke. Prosecutors insist he’s downplaying the sincerity of his views.

On the show, Berger and his cohost “halfheartedly claim that the discussion is a ‘prank’ and a ‘playful thought’,’ and they are not advocating for violence,” prosecutors wrote in a filing this week seeking a judge’s order to have Berger detained until his trial. “But it is clear that the discussions are serious.”

They raised the issue, they noted, not because anything Berger said on his show constituted a crime but rather to support their argument that he was unlikely to comply with any bail conditions set by the court given his antigovernment views.

Still, it was not Berger’s podcast that first drew the attention of federal authorities, according to court filings. Agents with U.S. Customs and Border Protection and Homeland Security Investigations intercepted three packages mailed to Berger’s address containing unregistered silencers imported from China.

They discovered the cache of 12 modified machine guns and 13 silencers during the January 2021 raid along with a 3D printer and plastic firearms magazines for handguns.

Prosecutors say the Bergers amassed their collection of weapons over 10 years. The younger Berger, they allege, modified the weapons himself and had expressed an interest in 3D printing of “ghost guns,” or untraceable firearms sold in parts and assembled by their users, on his podcast.

During Thursday’s hearing, the younger Berger offered little by way of response. As prosecutors pushed for him to be detained pretrial and his lawyer insisted they were overreacting, he sat quietly watching the proceedings behind a surgical mask while appearing in court from a federal detention center via video conference.

Ultimately, Carlos, the judge, granted the government’s request, but she noted it was not Berger’s podcast that swayed her.

“Just the sheer number of guns that are involved here — the fact that there’s silencers involved, the fact that there’s ammunition,” she said. “That’s concerning to the court.”

She had previously released Berger’s father on a $25,000 unsecured bond.

A trial date has not yet been set in the case. The Bergers could face up to 30 years in prison if convicted.