Santa Maria, Calif. – Sheriff’s detectives have arrested 20-year-old Nathaniel McGuire from Santa Maria for exploding and improvised explosive device at the Santa Maria Courthouse today. At approximately 8:48 am this morning, the Sheriff’s Office received a report of an explosion at the Santa Maria Court House near Department 9.

Sheriff’s deputies, along with Santa Maria Police officers, CHP, fire and medics responded to the scene where a male suspect, later identified as McGuire, had just entered the facility, threw a bag at the screening station, and the bag exploded in the hallway. Four victims were transported from the scene to an area hospital, and one victim arrived at the hospital on their own. Three of the five victims seen at the hospital were physically injured with non-life-threatening injuries, including burns. All the victims were treated and have since been released by the hospital.

Immediately after throwing the backpack, McGuire ran to the southeast parking lot where he was detained by a court security officer, a Sheriff’s Deputy and CHP Officers as he tried to enter his red sedan. McGuire was alone when he was apprehended and was wearing body armor underneath a jacket. He did not have any physical injuries from the explosion.

Responders established a perimeter of approximately five blocks around the court compound and evacuated the courthouse, surrounding homes, businesses and a school. The Sheriff’s Office Bomb Squad responded to the scene. 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 his residence.  Roadways in the areas surrounding the courthouse and the suspects residence were closed for several hours and have since been reopened.

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.  In that case, McGuire was arrested for possession of a loaded and concealed revolver that was not registered to him.  His arraignment for that arrest was schedule for this morning in Department 9 at the Santa Maria Court campus.

Detectives are working with SBC 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. McGuire has been booked at the Northern Branch Jail for felonies including attempted murder, manufacturing an explosive device and use of an explosive device for attempted murder.

At a press conference earlier today, Undersheriff Bonner said, “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. 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.”

Anyone with information about McGuire that could assist in this investigation is encouraged to contact the Sheriff’s Office Anonymous tip line at (805)681-4171.