A California man who had recently been arrested on a gun charge threw an explosive device into the Santa Maria courthouse where he was to be arraigned on Wednesday, injuring three people, officials said.

None of the injuries were life-threatening, and everyone who was hurt was treated at and released from a hospital, Santa Barbara County Undersheriff Craig Bonner said.

The suspect, Nathaniel McGuire, 20, of Santa Maria, was arrested as he tried to get into his car after the explosion around…