Is the following passage an argument or a non-argument? How can we tell? If it is an argument, what is the conclusion?

"An Amtrak train derailed yesterday near Newport, Virginia, injuring 74 people. Investigators from the National Transportation Safety Board suspect that the train's derailment was caused by vandals who tampered with the track's siding switch. Investigators believe this because the lock on the switch is missing and a pair of bolt cutters was found near the switch."