Rescue crews with sonar equipment suspended their search by 6 p.m. Sunday for two North St. Louis County men missing since their fishing boat capsized Saturday afternoon near Hartford.
The search ended just before nightfall because "we didn't want any personnel operating on or near the river after dark," said David Owens II, the Hartford fire chief.
The recovery operation is set to resume at 9 a.m. Monday, Owens said.
The two missing men, ages 49 and 60, have not been identified at the request of family members. A 10-year-old boy who fell out of the same boat was rescued unharmed from the river after about 10 minutes in the water.
While the boy was wearing a life vest, the two missing men apparently were not, Owens said.
High winds apparently played a role in the boat's capsizing, he said.
"Right now we're suspecting the high winds causing the condition of the river to be very hard to navigate," Owens said. "There were 4- and 5-foot swells, whitecaps."
About 30 personnel from six agencies, including the Illinois Department of Conservation, were involved in Sunday's search, Owens said.