NIAGARA, Wis. -- A man wearing camouflage clothing and carrying an assault rifle walked out of the woods and gunned down four young people who had gathered at a river to go swimming, killing three of them and wounding one.
More than 100 law enforcement officers from at least 10 agencies searched Friday for the gunman, a middle-age man who was last seen near the town of Niagara in northern Wisconsin, across the state line from Michigan's Upper Peninsula.
Officers set up roadblocks and evacuated an unknown number of homes.
Nine young adults had gathered near a railroad bridge on the Menominee River when the gunman came out of the woods and opened fire about 5:30 p.m. Thursday, according to Sheriff Jim Kanikula.
Authorities have not determined a motive. The sheriff said there was no communication between the gunman and his victims.
The shooter was only 7 to 10 feet away from one victim when he fired, the sheriff said.
On Friday, two of the bodies remained at scene about three miles west of Niagara because of fear that the shooter was still in the area.
The dead were identified as Tiffany Pohlson, 17; Anthony Spigarelli, 18; and Bryan Mort, 19. A fourth victim, 20-year-old Daniel Louis Gordon, was wounded.
Niagara is about 210 miles north of Milwaukee.