Route 28 was closed in both directions and the Loudoun County bomb squad was called to the scene of an accident Wednesday evening after a device believed to be a grenade was found inside of one of the cars.

According to Loudoun County sheriff’s deputies, the accident, a rear-end collision, took place shortly before 6:30 p.m. in the northbound lane of Route 28 (Sully Road), near Route 606.

A volunteer firefighter noticed the supposed grenade inside one of the cars involved in the accident. Sully Road was closed in both directions for nearly three hours while authorities investigated the device.

The bomb squad determined that the device was a harmless replica grenade, and the road was reopened about 9:30 p.m.

The accident remains under investigation.