Cobb school officials now say a report of an intruder with a knife on the campus of Lindley Middle School in Mableton were false.
Lindley was placed under lock down shortly after 10 a.m. today while school and police officials investigated and worried parents arrived at the school.
Police searched room-to-room looking for a man with a knife.
Students were held in their normal classrooms, according to a Doug Goodwin, a Cobb school spokesman.
When alerts were sent by news media, parents rushed to the school. Police asked them to wait at the Mt. Harmony Church at 561 Veterans Memorial Highway.