NBC Montana posted a video Thursday taken by a tourist during a road construction delay that shows two men teeing off with golf clubs on the side of the mountain road.
On Friday, Glacier spokeswoman Lauren Alley told the Missoulian the incident is under investigation.
She says throwing or hurling things over Going-to-the-Sun Road has the potential to hurt or kill people or wildlife.
She says anyone who spots such activity should try to record the person's license plate number or remember their face, if it can be done safely.
Alley says law enforcement calls at Glacier are up 40 percent over last year.
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