Streets surrounding Underground Atlanta have reopened after being shut down for several hours Tuesday morning as police investigated a bomb threat.

Police responded to a bomb threat call in the 100 block of Alabama Street around 4:30 am., according to police dispatch logs.

Atlanta police Sgt. Greg Lyon said just before 8 a.m. that the department’s bomb squad was investigating a “suspicious device” in a vehicle on Pryor Street.

Bomb technicians could be seen removing and opening a briefcase from the vehicle, a white Chevrolet Tahoe.

Lyon said the driver of the vehicle has been detained.

Decatur, Wall and Pryor streets as well as Martin Luther King Jr. Drive were blocked but reopened around 9 a.m.