The caller said there was a boating accident and one person was hurt.
Gregory Bykowski of Delafield was taken to Howard Young Medical Center where he later died.
Investigators say the 42-year-old was being pulled by a boat when the accident happened.
"An individual (Bykowski) being towed on an inflatable type device, a device that actually makes you go a little airborne if you hit a wave, apparently fell, hit the water pretty hard was knocked unconscious for a period of time," says Tom Wrasse, Woodruff Law Enforcement, "When they got him to shore he regained consciousness and was alert responding to questions. They took him to the hospital and shortly after 1:00 a.m. he succumbed to his injuries."
The accident is still under investigation.