The first-period bell rang in Southgate's Davidson Middle School on Thursday morning.
A 13-year-old walked into an empty second-floor bathroom with a .40-caliber handgun. A single shot rang out about 8 a.m.
The teen, found by a schoolmate, had committed suicide with a gun that belonged to a family member, according to police, the Free Press reported.
The teen -- whose name was not released by school officials or police -- was rushed to a hospital, where he was pronounced dead.