A Martinez Junior High School student was arrested on Tuesday after allegedly writing a threat on a bathroom mirror, according to police.
Police said officers were dispatched to the school at 1600 Court St. where the threat said that someone would "shoot up the school" on Wednesday. Officers were able to contact the suspect, a boy whose name is not being released, and arrested him.
Officers determined the threat wasn't credible, but police said they still took it seriously, and precautions were made to ensure the safety of students and staff.
The boy was booked into Contra Costa County Juvenile Hall.