Nathaniel McGuire, 20, has been charged with using a weapon of mass destruction, maliciously damaging a building with an explosive, and possessing unregistered destructive devices, the U.S. Attorney's Office in Los Angeles said in a statement.
McGuire was arrested Sept. 25 after officials say he threw a bag with explosives into the lobby of a courthouse in Santa Maria, a city of about 110,000 in California's central coast region. He told law enforcement he had planned to kill deputies and a judge in the building, officials said.
At McGuire's arraignment last month, U.S. Magistrate Judge A. Joel Richlin in Los Angeles ordered a mental health evaluation for him after he had an outburst, yelling about world events and blaming the government. He did not enter a plea and has remained in custody since his arrest.
Man threw explosive device inside Santa Maria courthouse on day of arraignment, officials say
McGuire is expected to appear in federal court again in Los Angeles on Friday. Federal public defender Iboh Umodu is representing McGuire and did not immediately respond to an emailed request for comment.
McGuire had been arrested in July on suspicion of illegal gun possession and was about to be arraigned at the Santa Maria Courthouse when the explosion went off. Federal authorities said he was arrested as he was trying to get into his car, which was parked nearby, and "yelled that the government had taken his guns and that everyone needed to fight, rise up, and rebel."
Law enforcement said they found ammunition, a rifle, a shotgun, a suspected bomb, fireworks, and 10 Molotov cocktails inside the car.
During a search of McGuire's home, they found an empty can with nails glued to the outside, a duffel bag containing matches, black powder, used and unused fireworks, and papers that appeared to be recipes for explosive material.
In a court filing, federal authorities said McGuire told law enforcement after his arrest that he had gone to the courthouse planning to kill deputies working at the security desk and after throwing the bag yelled "Liberty or Death." Authorities said he told them he planned to go back to the car to get weapons and reenter the courthouse to kill a judge.
"The new charge of using a weapon of mass destruction underscores how seriously we are treating this misconduct and my office's determination to hold accountable those who seek to bring violence upon our courts, law enforcement personnel, and the public," United States Attorney Martin Estrada said in a statement.
McGuire has also been charged by Santa Barbara County prosecutors with 10 counts, including two counts of attempted murder, use of an explosive device with the intent to murder, and carrying a loaded firearm. He is also being charged with arson of forest land in connection with three fires on the outskirts of Santa Maria.