SANTA MARIA, Calif. (AP) — A man set off an explosive device in the lobby of a California courthouse on Wednesday, injuring five people and prompting the shutdown of the court complex and other city buildings, officials said.

A suspect was detained following the explosion that was reported shortly after 8:45 a.m. at the Santa Maria Courthouse in Santa Maria, sheriff’s officials said. The small city of about 110,000 people is in Santa Barbara County, in California's central coast region.

“Scene remains active. Please continue to avoid the area,” county sheriff's spokesperson Raquel Zick posted on the social platform X.

Zick later said the person detained was a man and that the blast came from “an intentionally set” explosive device. She said investigators don't believe there are any other suspects.

“The bomb team is processing the scene and the suspect is still being interviewed,” Zick later said on X.

The sheriff's department initially said two people sustained non-life-threatening injuries, but Sandy Doucette, a spokesperson for Marian Regional Medical Center, said the hospital was treating five patients in connection with the explosion. Two were in good condition and three in fair condition on Wednesday morning, Doucette said, without providing details of their injuries.

Darrel Parker, court executive officer in Santa Barbara County, said the explosion occurred in the first-floor lobby of the criminal court building, which serves as the entryway and weapons screening point for the broader court campus. Anyone who wants to go to criminal, civil or other courts must pass through there to do so, Parker said.

“I am not certain that the suspect made it past weapons screening,” Parker said.

Shane Mellon told KSBY-TV that he was at the courthouse when he heard what sounded like chairs falling over.

“It was a loud bang,” he said, adding the bailiff escorted him and others out.

Mellon said he saw what looked like a sweater smoldering and a man screaming while four or five people got on top of him, trying to keep him restrained.

“I think this could have been way worse than it was if not for the deputies just jumping on top of that guy,” Mellon said.

The office of California Gov. Gavin Newsom said it was monitoring the situation and coordinating with local law enforcement.

The courts were closed on Wednesday and filing extensions will be offered for those affected by the shutdown. Parker said he expects the court to resume operations on Thursday.

Patrols were stepped up at courthouses in neighboring Los Angeles County, the sheriff's department there said.

Santa Maria City Hall, which is near the courthouse, was also closed Wednesday due to the ongoing investigation, said Mark van de Kamp, a spokesperson for the city. So were other nearby city offices in addition to branch libraries that depend on the city’s main library for support, he said.

The courthouse holds state and county courts in the city of Santa Maria, which is about 150 miles (240 kilometers) northwest of Los Angeles. Two decades ago, the courthouse was where Michael Jackson was tried and acquitted of sexual abuse.