File Photo / San Francisco Chronicle archives

A 13-year-old Antioch girl was arrested on suspicion of weapons-related charges after she accidently shot herself in the hand with a gun she said she found in a school bathroom, city officials said.

Around 7:30 p.m. on Wednesday, officers responded to Sutter Delta Medical Center in Antioch where the girl was being treated for the injury, according to a report from Acting City Manager Ron Bernal. The teen told officers she had found the revolver in a school bathroom then placed it in her backpack, where she kept it all day. The report did not provide the name of the school.