PINOLE (CBS SF/BCN) — Pinole Police cited a 12-year-old student for allegedly threatening a shooting at Pinole Middle School earlier this week, officers reported Friday.

In a press release published on Facebook Friday, Pinole police said they were contacted at about 8:20 p.m. Monday about an email sent to school staff about a shooting at the campus on Mann Drive the next day.

READ MORE: KPIX Reporters Remember Slain Security Guard Kevin Nishita; 'Just the Kindest Man'

Investigators identified the suspect as the 12-year-old, who confessed to sending the email, police said.

READ MORE: UPDATE: News Crew Security Guard Shot in Oakland Dies From Injuries; Photo of Suspect Vehicle Released

The student, who is not being identified, was cited for threatening violence on school grounds and was released to the custody of a parent.

The case was the second involving a firearm at Pinole Middle School this week. At 8:58 a.m. Monday, school officials called Pinole police about a student possibly in possession of a gun on campus, and officers found a pellet gun in a backpack, according to police.

MORE NEWS: Burlingame Shoppers Show Up for Small Business Saturday

No other details about the response, which prompted a campus lockdown, were immediately available.