Man set off bomb at courthouse ahead of arraignment on gun charges, officials say

A man who authorities believe set off a bomb at a Santa Barbara County courthouse Wednesday morning did so on the day he was scheduled to be arraigned on gun charges.

According to the Santa Barbara County Sheriff’s Office, 20-year-old Nathaniel McGuire detonated a homemade bomb inside the courthouse in Santa Maria, located on the Central Coast, about an hour north of Santa Barbara.

Authorities responded to the Santa Maria courthouse around 8:50 a.m. after a man, believed to be McGuire, entered the facility and threw a bag at the security screening station.

The bag exploded and McGuire fled to his parked car, but was apprehended by a court security officer, a Sheriff’s Deputy and a California Highway Patrol officer, officials said during an afternoon press conference in Santa Maria.

McGuire, a resident of Santa Maria, was wearing body armor under his jacket at the time of his arrest, Santa Barbara County Undersheriff Craig Bonner said. McGuire was uninjured in the blast.

Following the explosion, local law enforcement and paramedics rushed to the scene after receiving word of at least two injuries.

The number of victims eventually grew, with four people being transported to a local hospital, Bonner said. An additional victim later arrived at the hospital on their own, he added.

Three of the people hospitalized suffered “physical” injuries, including burns, that were not believed to be life-threatening. All of the injured victims have since been treated and released, Bonner said.

Around 10:30 a.m., Sheriff’s Office spokeswoman Raquel Zick said in a post to social media that the scene had not yet been deemed safe and urged citizens to avoid the area while law enforcement investigated.

As the investigation intensified, authorities began evacuating homes, businesses and a school within a five-block radius of the courthouse.

“In the hours that followed, the bomb squad worked to render the scene safe and check for any additional unexploded devices in the courthouse, the suspect’s vehicle and at his residence in Santa Maria,” Bonner said.

Detectives believe that McGuire’s motivation for the alleged attack stemmed from a July arrest for firearms violations. On July 28, 2024, the 20-year-old was arrested after sheriff’s deputies discovered an unregistered and loaded resolver on his person.

McGuire’s arraignment in that case, according to Bonner, was set to take place Wednesday morning at the Santa Maria courthouse.

Detectives are working with the Santa Barbara County Fire Department to investigate a possible link between the courthouse bombing and other arsons that have taken place in the area.

McGuire is being held in jail without bail, and is expected to face multiple charges, including attempted murder, using an explosive device in attempting to kill someone and possession of explosive devices.

“Although this is an ongoing investigation, and we are exploring all possible angles, we do believe this to be a local incident, committed by a local individual with a local grievance stemming from his arrest,” Bonner said. He added that the Sheriff’s Office did not believe there to be any remaining threat to the public.

The FBI has launched its own investigation in collaboration with the Sheriff’s Office, and officials said it does not believe McGuire has any known ties to terrorist groups.

The investigation is ongoing and anyone with information is urged to contact the Santa Barbara County Sheriff’s Office tip-line at 805-681-4171.

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