A bomb squad exploded a suspicious object found behind the federal building in Harrisburg Tuesday morning.

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The federal building in Harrisburg was evacuated after a suspicious Thermos suspected of being an explosive device was found behind the building around 8:30 a.m. during a routine security sweep. Police in Harrisburg closed streets and sidewalks in the area.

The Penn State Bomb Disposal Squad X-rayed the device and was unable to determine what was inside, so the unit exploded the device.

The FBI determined the suspicious object was not an explosive device because it did not have an ignition device, so it could not have exploded on its own. The package is still considered suspicious, because they are not clear what was inside it. The debris will be sent to the FBI lab in Philadelphia to determine what it was.

Bomb dogs swept the building to make sure it was safe before about 350 people were allowed to return to the building Tuesday afternoon.