A fisherman found the body floating near some boats, according to a witness.
Last Friday evening, Maddula was with friends at an off-campus party. He and others left around 12:30 a.m. Saturday morning, heading -- it is believed -- for another party when Maddula disappeared.
On Wednesday, divers searched the lake near Wilmette Harbor after they discovered Maddula's phone last pinged off a cell tower in that area just about an hour after he left the party.
"That ping would have been early Saturday morning sometime around 1a.m. or thereafter. Based on that it's believed this is the closest to his last known location," Alan Cubbage, Northwestern University spokesperson, said.
Divers from the U.S. Coast Guard and local fire departments were involved in the water search. Crews using dogs also looked at boats docked in the harbor and the area nearby.
Maddula's parents flew to the Chicago area from Long Island, New York, earlier in the week to help in the search.