A man wearing body armor detonated an explosive device inside a courthouse in Santa Maria, California, on Wednesday, injuring multiple people before he was arrested, authorities said.
The man, who authorities identified as Nathaniel McGuire, 20, of Santa Maria, entered the courthouse Wednesday morning to attend an arraignment for a July arrest on a firearms violation, said Santa Barbara County Undersheriff Craig Bonner.
McGuire threw a bag at the screening station, causing an explosion in the hallway that injured several people. He then ran to a parking lot where law enforcement officers detained him. McGuire was wearing body armor under his jacket and was not injured, authorities said.
The FBI and local authorities said it was an isolated event and not tied to terrorism.
McGuire is being held without bail on charges including attempted murder, using an explosive device in attempting to kill someone, and possession of explosive devices.
The sheriff's office is also working with the Santa Barbara County Fire Department to investigate whether McGuire is linked to several recent arsons, Bonner said.
According to Bonner, the sheriff's office received a report of an explosion at 8:48 a.m. local time at the Santa Maria Court Complex near the courtroom where arraignments take place and where McGuire was set to appear Wednesday.
The court compound was evacuated, as well as nearby homes, businesses and a school, authorities said. The City of Santa Maria said that its City Hall, finance department, city attorney's Office, public library and recreation and parks department would reopen Thursday.
Six people were treated at and released from Marian Regional Medical Center in Santa Maria on Wednesday, said Joe Bailey, a spokesperson for Dignity Health, which operates the hospital. They are believed to be bystanders and not court employees, said Darrel Parker, the court's executive officer.
Adrian Paris, a lawyer at a San Diego-based firm, was in the gallery of a courtroom in the complex when he heard a loud bang.
"It was an explosion of some kind," Paris, 36, said in a telephone interview Wednesday night. "That explosive pop, it's really distinct. There's no other way to describe it."
A few seconds later, the building's alarms started blaring, there was loud chatter on the court bailiff's walkie-talkie and everyone was led out of the building.
As Paris left he heard shouting and saw a jacket on the ground that had "fire and smoke coming off of it," he said.