NORFOLK, Va. (AP) — Federal agents found one of the largest stockpiles of homemade explosives they have ever seized when they arrested a Virginia man on a firearms charge last month, according to a court filing by federal prosecutors.

Investigators seized more than 150 pipe bombs and other homemade devices when they searched the home of Brad Spafford northwest of Norfolk in December, the prosecutors said in a motion filed Monday. The prosecutors wrote that this is believed to be “the largest seizure by number of finished explosive devices in FBI history.”

Most of the bombs were found in a detached garage at the home in Isle of Wight County, along with tools and bomb-making materials including fuses and pieces of plastic pipe, according to court documents. The prosecutors also wrote: “Several additional apparent pipe bombs were found in a backpack in the home’s bedroom, completely unsecured,” in the home he shares with his wife and two young children.

Spafford, 36, was charged with possession of a firearm in violation of the National Firearms Act. Law enforcement officers allege he owned an unregistered short barrel rifle. Prosecutors said that he faces “numerous additional potential charges” related to the explosives.

Defense attorneys argued in a motion Tuesday that authorities haven’t produced evidence that he was planning violence, also noting that he has no criminal record. Further, they question whether the explosive devices were usable because “professionally trained explosive technicians had to rig the devices to explode them.”

“There is not a shred of evidence in the record that Mr. Spafford ever threatened anyone and the contention that someone might be in danger because of their political views and comments is nonsensical,” the defense lawyers wrote.

Messages were left Wednesday seeking further comment from the defense lawyers who signed the motion, Lawrence Woodward and Jerry Swartz.

The investigation began in 2023 when an informant told authorities that Spafford was stockpiling weapons and ammunition, according to court documents. The informant, a friend, told authorities Spafford had disfigured his hand in 2021 while working on homemade explosives. Prosecutors said he only has two fingers on his right hand. The informant told authorities that Spafford was using pictures of the president, an apparent reference to President Joe Biden, for target practice and that “he believed political assassinations should be brought back,” prosecutors wrote.

Numerous law enforcement officers and bomb technicians searched the property on Dec. 17. The agents located the rifle and the explosive devices, some of which had been hand-labeled as “lethal” and some of which were loaded into a wearable vest, court documents state. Technicians detonated most of the devices on site because they were deemed unsafe to transport, though several were kept for analysis.

At a hearing Tuesday, federal Magistrate Judge Lawrence Leonard determined that Spafford could be released into house arrest at his mother’s home but agreed to keep him detained while the government files further arguments.

In response, prosecutors reiterated why they believe Spafford is dangerous, writing that “while he is not known to have engaged in any apparent violence, he has certainly expressed interest in the same, through his manufacture of pope bombs marked ‘lethal,’ his possession of riot gear and a vest loaded with pipe bombs, his support for political assassinations and use of the pictures of the President for target practice.”