Coast Guard searching for at least 1 missing person after boat sinks near 31st Street Harbor

CHICAGO (WLS) -- A water search is underway after a boat capsized in Lake Michigan on Chicago's South Side.

The U.S. Coast Guard said they received calls about a 25-foot double-decker pleasure yacht capsizing and then sinking near the 31st Street Harbor. Chicago police said it happened around 7:30 p.m.

The Coast Guard said 16 people were on the boat at the time of the incident. It was not immediately clear how many of them went into the water, but as of 9 p.m., Chicago police and the Coast Guard said at least one person, an adult male, was still unaccounted for.

Three people, a man and two women, were taken to a local hospital for treatment after the incident, all in good condition, police said.

A witness said he saw the boat speeding in the water before flipping over, and then he heard screams for help.

A group called Boat Safe Chicago captured drone video of the wreckage just moments after the crash.

The search for the missing person, or people, is ongoing by Chicago police with assistance from a helicopter in the air.