Authorities say a pipe bomb was found inside a storage unit on Wednesday evening in Prince George’s County, Maryland.

A spokesman for the Prince George’s County Fire and EMS Department told WTOP that around 5:35 p.m. they received a 911 call from workers cleaning out a storage unit at a facility on Suitland Road near Ewing Avenue in the Hillcrest Heights area.

Inside, the workers had found a 12-inch long steel pipe with a fuse, which they suspected was a pipe bomb.

The bomb squad from Prince George’s County Fire was called in, and after confirming it was an active explosive device, the bomb squad safely disabled it around 9:30 p.m.

Investigators are working to find out who is responsible for leaving the device in the facility.

The Prince George’s County Bomb Squad and Fire Marshall are leading the investigation with assistance from Prince George’s County police and the Bureau of Alcohol, Tobacco, Firearms and Explosives, also known as the ATF.