German police hunting man who entered school with gun

German police on Monday were hunting for a man who entered a high school in southwestern Germany with a firearm -- but authorities initially arrested the wrong man.

The armed man entered the Friedrich Ebert School in Esslingen, near Stuttgart, prompting a lockdown, police spokesman Bjoern Reusch said. The man didn't use the weapon and was only briefly in the school.

Police searched the building and initially arrested a man, but let him go after realizing he wasn't the gunman.

Police believe the suspect, who was described as wearing a red T-shirt, blue jeans and reading glasses, fled on a motor bike.