WINONA Minn. — A 15-year-old boy jumped out of a boat into the Mississippi River, apparently during a domestic dispute, and swam to the downtown Levee. At the Levee, as the sheriff’s drive and rescue team and a second sheriff’s water crew watched, the teen-ager threatened suicide by jumping off a ledge. A city police officer at the Levee distracted the man for a moment, and another officer grabbed him. The boy was taken to the hospital for evaluation.