The FBI uncovered more than 150 homemade bombs on a farm in Virginia in what is thought to be the largest such seizure in the agency's history, according to court documents filed this week.

Agents found the explosives while searching the family home of 36-year-old Brad Spafford after being tipped off by a neighbor that he was stockpiling weapons and homemade ammunition.

A court document filed Monday said Spafford, who works at a machine shop, had used pictures of President Joe Biden for shooting target practice and expressed support for political assassinations.

Some explosives assessed as pipe bombs were found in a backpack in a bedroom on the property, which Spafford shares with his wife and two young children, the document said. It added that Spafford's freezer contained a jar of HMTD -- a "highly unstable" explosive device -- stored alongside food and labeled "Do Not Touch."

His home also had a notebook of "recipes" for making explosives including grenades, according to the filing.

A neighbor told FBI agents that Spafford had discussed fortifying his property with "a 360-degree turret for a 50-caliber firearm on the roof."

Prosecutors said Spafford, who has been charged with unlawful possession of a rifle, would likely face additional charges over the explosives, which each carry a maximum sentence of ten years of imprisonment.

In a separate filing on Tuesday, Spafford's attorneys defended him as "a hard-working family man with no criminal record" while arguing for him to be released from custody.