An unusual drama that began around noon and continued after nightfall unfolded in San Jose’s Japantown on Tuesday, as an entire residential block was evacuated so a bomb squad could blow up a cache of explosives found along with several guns inside a suspect’s house.

Sixty-three-year-old Mark Sedlock was arrested on suspicion of making criminal threats, possession of firearms and possession of explosive materials after officers found the weapons while executing a search warrant.

As Tuesday’s events progressed, onlookers sat on lawn chairs in the background as authorities shouted, “Fire in the hole! Fire in the hole!” before the detonation.

PG&E crews shut off utilities to the home, police said, and hazardous material crews, police investigators and bomb squad technicians determined the best way to safely detonate the materials was to blow them up.

Officers dug a 3-foot hole in the front yard, surrounded it with sand bags piled 3 feet high, moved the material from the home into the hole and set off a gunshot-like explosion that captivated bystanders like a fireworks show.

A small flame flickered in the distance and a gust of white smoke shot up from the hole. About an hour later, at 7:15 p.m., they blew up what they thought was the rest of the explosives.

But as officers re-entered the home on Sixth Street, near Washington Street in Japantown, they found more explosives, police said. They planned to blow those up, too, or find a way to safely get them away from the scene.

Ten homes were evacuated during the search, and it was not immediately clear when residents might be allowed to return. No one was injured.

Officers took Sedlock into custody at 12:30 p.m., and he remained in Santa Clara County Jail Tuesday night. Bomb squad technicians came on the initial call with the officers, since they had reason to believe Sedlock had some explosive materials in his home, said Officer Jose Garcia, a San Jose police spokesman.

Contact Mike Rosenberg at 408-920-5705.