SANTA MARIA, Calif. (AP) — An explosive device that authorities said was intentionally set has injured two people at a California courthouse on Wednesday, authorities said.

One person of interest was detained following the blast 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 in Santa Barbara County is in California’s central coast region.

“We have two reports of non-life-threatening injuries. One person of interest detained immediately. Scene remains active. Please continue to avoid the area,” Santa Barbara County Sheriff Public Information Officer Raquel Zick said on the social platform X.

Zick later said the person detained was a man and the blast came from “an intentionally set” explosive device.

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.

A spokesperson for the Santa Barbara County Sheriff’s Department declined to immediately provide additional information.

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

The website for the Superior Court in Santa Barbara County said the courthouse complex was closed for the day and all courtroom calendars were canceled. Phone and email messages were left for Darrel Parker, the court’s executive officer.

Santa Maria City Hall, which is located near the courthouse, was 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.