Man tossed explosive device into courthouse ahead of arraignment, policy say

A California man set to be arraigned at the Santa Maria Courthouse on Wednesday was charged in connection with the on-site explosion earlier that morning that injured five individuals and put the area on lockdown, the Santa Barbara County Sheriff’s office said.

Police identified 20-year-old Nathaniel McGuire from Santa Maria as the suspect in the incident, according to a press release. He was booked at the Northern Branch Jail on felony charges, included attempted murder, manufacturing an explosive device and use of an explosive device for attempted murder.

McGuire was slated to be arraigned later Wednesday morning on separate charges, after he was arrested on July 28 for possession of a loaded and concealed revolver that was not registered to him.

“Through their investigation, detectives learned that McGuire’s motivation appeared to have stemmed from a recent arrest by the Sheriff’s Office on July 28, 2024, for firearms violations,” the press release said.

Police said McGuire entered the facility Wednesday morning, threw a backpack at the screening station, and then the bag exploded in the hallway. He was detained by a court security officer, a sheriff’s deputy and California Highway Patrol officers, as he tried to flee in his red sedan, police said.

McGuire was wearing body armor under his jacket, when he was apprehended, and he was not injured by the explosion, according to police.

Four individuals were injured and transported to the hospital from the scene, and one additional victim arrived at the hospital later on their own. Three of the five individuals were hurt with non-life-threatening injuries, including burns, the police said. All victims have since been released from the hospital.

Roadways in the area surrounding the courthouse and the suspect’s home were closed for several hours on Wednesday, police said, but they have since been reopened.

Police said detectives are working with Santa Barbara County Fire investigators “to explore if the suspect is associated with several recent arson fires, and they are in the process of serving search warrants for McGuire’s car and home,” according to the press release.

“Although this is an ongoing investigation and we are exploring all possible angles, at this point in time, we believe this to be a local incident committed by a local individual, with a local grievance stemming from his arrest,” Undersheriff Craig Bonner said at a press conference on Wednesday.

“We are not absolutely ruling out that there is something larger at play but at this time we believe this is a local matter that has been safely resolved and there are no outstanding community safety concerns. We will be sharing his booking photo and are asking the public to contact our detectives with any information relative to this investigation,” he continued.