ST. LOUIS — Governor Jay Nixon of Missouri and Governor Bruce Rauner of Illinois toured flood-ravaged areas Saturday as near-record crest predictions of the Mississippi River and levee breaks threatened more homes.

The flood, fueled by more than 10 inches of rain over a three-day period that began last weekend, is blamed for 24 deaths. Searchers were still looking for four missing people.

In central Illinois, the body of one of two teenagers missing since Monday was located on Friday. Devan R. Everett, 18, was found in the water near where dive crews found the pickup truck he and the other teen were last seen in.

On Saturday, Illinois’s governor resumed his tour of flood-damaged areas for a second day, with planned stops in Cairo and Olive Branch. A day earlier he activated Illinois National Guard soldiers to help with flood recovery efforts as needed. In Missouri, Nixon planned stops in Eureka and Cape Girardeau.

In St. Mary, Mo., a town of about 360 residents 50 miles south of St. Louis, neighbors and volunteers placed sandbags around homes after a small agricultural levee broke. The Mississippi River was expected to crest there Saturday at about 3½ feet below the 1993 record.

The main culprit in the St. Louis region was the Meramac River, a relatively small Mississippi tributary. It had flooded communities in the far southwestern reaches of the St. Louis suburbs during the week. By Friday, it was relenting, but not before some points topped the 1993 record by 4 feet.

Two waste-water treatment plants were so damaged by the flood waters that raw sewage spewed into the river. A water plant closed at High Ridge.

Hundreds of people were evacuated in Pacific, Eureka, Valley Park, and Arnold, and many of their homes took in water.

Among those displaced were Damon Thorne, 44, and his 60-year-old mother, Linda, who live together in an Arnold mobile home park that washed away after a small private levee proved no match for the surging Meramec. For now, the Thornes are staying in a Red Cross shelter at a Baptist church.

‘‘We’re just basically homeless,’’ Damon Thorne said. ‘‘We have nowhere to go.’’