FBI investigation of a Virginia man led to what the agency calls its largest-ever seizure by number of finished explosive devices.

Prosecutors are fighting to keep a Virginia man behind bars after they say investigators found what could be the largest number of “finished explosive devices” in FBI history at his 20-acre home near Norfolk.

The FBI found more than 150 homemade bombs during a raid on a Virginia farm when they arrested a man on a firearms charge, federal prosecutors allege. The big picture: Preliminarily assessments of the haul seized from Brad Kenneth Spafford's Isle of Wight County farm indicate it's "the largest seizure by number of finished explosive devices in FBI history,