Man tossed bomb into California courthouse, injuring six, authorities say

Six people were injured after a 20-year-old man tossed a backpack that exploded at a security screening area of a courthouse in Santa Maria on Wednesday, authorities said.

The loud explosion left the courthouse filled with smoke as Santa Barbara County sheriff’s deputies, Santa Maria police and California Highway Patrol officers scrambled to find and hold the suspect down outside the courthouse.

The suspect had been due to appear in court Wednesday to face a charge over a firearm violation, Undersheriff Craig Bonner said during a news conference.

The man was identified as Nathaniel McGuire, a Santa Maria resident who was arrested July 28 after deputies found him carrying a loaded revolver that was not registered, Bonner said.

“At this point, we do believe this to be a local incident, involving a local resident, with a local grievance,� Bonner said.

The blast from the backpack was caused by “an intentionally set improvised explosion device,� a Santa Barbara County Sheriff’s Office spokesperson said in a social media post.

A witness told The Times that the explosion filled the courthouse with smoke and that a man being detained by law enforcement appeared to have ammunition falling out of his pockets and clothes as officials held him on the ground.

“I could hear the guy that apparently threw the bomb screaming at the top of his lungs and yelling,� said Shane Mellon, who represents a company that was scheduled to appear in court. “While they were holding him down and getting his clothes off of him, bullets were coming out of his pockets. Ammunition was just spreading everywhere.�

Mellon said he was inside a courtroom when he heard the loud bang, sounding like metal chairs falling over. When police escorted people out of the courtroom, the entrance to the building was filled with smoke, and a sweater on the ground appeared to be smoldering.

“This could have been much worse,� he said.

The explosion was reported at 8:48 a.m., triggering a rapid response from Santa Maria police and Santa Barbara sheriff’s deputies.

Five people were taken to Marian Regional Medical Center after the explosion, said Joe Bailey, a spokesperson with the hospital.

They were reported to be in “fair� and “good� condition, Bailey said, meaning their vital signs were stable and normal.

A sixth person went to the hospital later in the day, he said. Their condition was not immediately known. The Sheriff’s Department said victims’ injuries included burns. All had been treated and released by the hospital by Wednesday evening.

Bonner said McGuire was at the screening station for the courthouse Wednesday morning when he tossed the bag into the building.

The suspect was wearing body armor under his jacket, Bonner said.

Sheriff’s officials cordoned off a five-block area to secure the zone as a precaution, he said. The department’s bomb squad unit also searched the court, McGuire’s car and his house for any other possible explosive devices.

McGuire was being booked into county jail on suspicion of multiple crimes, including attempted murder, using an explosive device to attempt to kill someone, and possession of explosive devices. He was being held without bail, Bonner said.

No other suspects were believed to have been involved, Bonner said. By Wednesday afternoon, the sheriff’s bomb team was searching the area, and the suspect was being interviewed.

The Sheriff’s Department said detectives were working with Santa Barbara County Fire investigators to explore if the suspect was associated with several recent arson fires, and they were in the process of serving search warrants for McGuire’s car and home.

Mellon said he and other people being escorted out of the building saw police take the suspect into custody on the sidewalk, just outside the building.

He said he could hear the man yelling, “We gotta fight back� and “You gotta fight back.�

“It was a little nerve-racking, watching it happen,� Mellon said.

Ted Docks, special agent in charge of the criminal division of the Los Angeles FBI field office, said the agency was assisting local authorities with the investigation.

Darrel Parker, court executive officer with the Santa Barbara County Superior Court, said the Santa Maria court would remain closed Thursday.

Gov. Gavin Newsom’s office and the governor’s Office of Emergency Services were in touch with local law enforcement agencies and monitoring the incident, Newsom’s office said in a post on X.

The explosion prompted city officials to temporarily lock down other public facilities nearby, including Santa Maria’s City Hall, Finance Department, library and Recreation and Parks Department as a precautionary measure.

Roads were closed for several hours in the areas surrounding the courthouse and the suspect’s residence. They have since been reopened.