Federal agents found one of the largest stockpiles of homemade explosives they have ever seized when they arrested a Virginia man last month, according to a court filing.

Authorities said an informant witnessed Brad K. Spafford use photographs of President Joe Biden for target practice.

Prosecutors say federal agents found one of the largest stockpiles of homemade explosives they’ve ever seized when they arrested a Virginia man on a firearms charge last month.

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.