The search of a vehicle pulled over by police for a traffic violation near San Leandro and Marina boulevards led to the discovery of a suspicious device in the trunk of the car, Tudor said.
The area was evacuated and a bomb squad arrived at the scene to investigate, Tudor said.
The device "did not contain an explosive," Tudor said.
Tudor, who was not at the scene, reported that the package was covered in what appeared to be duct tape and had wires attached to it.
He also said there was an older model cell phone attached to the package.
"It was a fake device, something this guy just made," Tudor said.
The incident caused precautionary closures at the Coliseum, San Leandro and Bay Fair BART stations starting at around 8:30 a.m., BART spokesman Linton Johnson said.
The car containing the suspicious device was about 20 yards from BART tracks, Johnson said.
All three stations had reopened as of 10:11 a.m., according to BART officials.
No further delays were expected.
The incident remains under investigation.