FBI to investigate Amtrak Train Likely Hit By Rock [VIDEO]

The FBI will meet with transportation investigators Monday to examine the damaged windshield of an Amtrak locomotive that derailed in Philadelphia, to help determine what struck the train just before the fatal wreck.

The mystery surrounding the crash deepened late last week after an assistant conductor told investigators the train may have been hit by some type of projectile just before hurtling around a sharp curve and running off the tracks.

“We do have this mark on the windshield of the Amtrak train, so we certainly want to trace that lead down,” National Transportation Safety Board member Robert Sumwalt said Sunday on CNN’s “State of the Union” program. The Federal Bureau of Investigation will be on scene Monday “to assist us in identifying what that may have been,” he said.