ST. LOUIS — Police are investigating after eight bullets were fired into the side of a light rail train near St. Louis.

Authorities say passengers ducked for cover Tuesday night when the shots were fired from an unknown location as a MetroLink train was leaving the station in Washington Park, Illinois. The train operator and the 20 passengers were unhurt.

The operator pulled into a station in Fairview Heights, Illinois, and called for help. Officers found eight bullet holes and determined the shots were fired from someone outside the train.

MetroLink trains serve portions of St. Louis city and St. Louis County in Missouri, as well as Illinois suburbs.