They detonated a car with the explosives found inside the man's home as part of their legal case. It destroyed the car in less than a second.
Investigators said the car's carcass and the videotape of the explosion will be used as evidence in their case.
KCRA reported the Delta Regional Auto Theft Task Force said it found two canisters of cast boosters, which are used for commercial purposes, inside Williamson's home.
It took just one of the canisters to blow up the car.
"The windshield's gone, there's twisted metal ... that's serious stuff," San Joaquin County Deputy District Attorney Katherine Mahood told KCRA.