US: Mystery gunman kills swimmers

Three teenagers preparing to go for a river swim were shot dead by a man armed with a rifle.

The middle-aged man, wearing camouflage clothing, walked out of woods in the Wisconsin town of Niagara, and opened fire killing the three instantly and wounding a fourth.

More than 100 police from at least 10 agencies joined the search today for the gunman.

The victims were near a bridge on the Menominee River when the gunman shot them on Thursday.

Two of the bodies had not been removed from the scene because of fears the shooter was still in the area.

The dead were identified as Tiffany Pohlson, 17; Anthony Spigarelli, 18; and Bryan Mort, 19. Daniel Gordon, 20, was wounded.