Towers High School in Decatur is on lockdown.
DeKalb police Capt. Steven Fore told Channel 2 Action News that an officer was making a traffic stop on Sherrydale Lane when three people got out of the car and ran.
Two of the three people are in custody, Fore said. A search is underway for the third person.
DeKalb County Schools spokesman Quinn Hudson told Channel 2 that Towers will release at the normal time of 3:30 p.m. There are about 1,000 students at the school, which is at 3919 Brookcrest Circle.