FBI determines derailed Amtrak train wasn't struck by bullet

PHILADELPHIA, May 18 (UPI) -- The FBI has determined an Amtrak train that derailed near Philadelphia killing eight people was not struck by a bullet prior to the crash, officials said Monday.

The National Transportation Safety Board, which is investigating the cause of the crash, asked the FBI to use its forensic resources to determine what caused damage to the lower left-hand side of the train's windshield.

"The FBI found no evidence of damage to Amtrak 188 windshield that could have been caused by a firearm," an NTSB tweet said.

The NTSB said it has not ruled out the possibility another object may have struck the windshield just prior to the May 12 crash that killed eight people and injured more than 200.

One of Amtrak train 188's conductors told investigators she heard the train's engineer, Brandon Bostian, talking via radio with a local Philadelphia train engineer. The other engineer allegedly told Bostian "he had been either hit by a rock or shot at" and Bostian replied that he experienced the same thing.

The NTSB said the investigation into the deadly crash could take up to 12 months.