WESTMINSTER -- Railroad officials said it was a tree stump intentionally left on tracks that derailed four locomotives and 16 cars of a freight train Monday.

BNSF officials has put up a $10,000 reward for information of those responsible. BNSF spokesman Steve Forsberg didn't know the exact size of the stump but said it would have required at least two people to move it.

Forsberg said Tuesday the stump got caught on a switch on the tracks, causing the first of four locomotives to lift up, triggering the derailment.

It was the second stump placed on the tracks. A few hours earlier, another stump was left of the tracks near 9030 Pierce Street, but an officer removed it.

The train carrying lumber and building materials jumped the tracks about 10:35 p.m. Monday. The train contained four locomotives and 37 rail cars.

Three crew members were aboard when the derailment occurred. One was transported to a hospital with minor injuries.

If you have information about the case, please call 1-800-832-5452. If you wish to remain anonymous, call Crime Stoppers at 720-913-STOP.