What appears to be a pipe bomb has been thrown through the window of the Wangaratta Chronicle newsroom.
No one has been injured but the newsroom has been evacuated and the police bomb squad have been on the scene.
A cleaner discovered the device, with wires attached, at 6am on Tuesday.
The bomb squad has since moved the device into the car park, and cordoned off the area from the public.
Police say the device was thrown through the Chronicle's window, slamming into the newsroom's back wall before landing on the floor.
Wangaratta Detective Senior Constable Paul Campbell told Fairfax that police had moved the device out of the building to the rear car park.
"There appears to be a device with some sort of wires that have come out of it, fashioned to look like what we might describe as a pipe bomb," he said.
"We certainly don't seem to have anyone with particular issues with the Chronicle ... it might be just a prank."
At 1.40pm there were reports from the scene that the device had been destroyed in a controlled explosion.
The Chronicle is Wangaratta's major newspaper.