CHICAGO (CBS) — Rescue teams on Saturday evening were searching for a boater who vanished in Lake Michigan.

It happened near Indiana Harbor in East Chicago, Indiana. There were four people in the boat when it turned over.

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At 3:27 p.m., the U.S. Coast Guard sent out a 45-foot vessel and rescued two of the people who had been in the boat. A good Samaritan rescued the third.

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One of the people who were rescued was in critical condition, while the other two were being treated for hypothermia.

The fourth person on the boat was still missing Saturday night.

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Coast Guard Station Chicago was working with the local fire department to find the boater who remained missing. A helicopter was sent from Air Station Traverse City to assist.

CBS 2 Chicago Staff