US: 17-year-old killed, 4 hurt in stabbings on Wisconsin river

A Minnesota teenager died and four other people were critically wounded after being stabbed while tubing down a Wisconsin river, authorities in the United States said.

St. Croix County Sheriff Scott Knudson the victims and suspect, a 52-year-old Minnesota man, were all on the Apple River when the attack happened on Saturday afternoon.

Knudson said investigators were working to determine what led to the stabbings and whether the victims and suspect knew each other.

They were tubing with two different groups that included about 20 people.

"We don’t know yet who was connected to who, who knew each other or what precipitated it," Knudson said.

The knife attack happened on a difficult-to-access section of the river near the town of Somerset, Wisconsin, which is about 35 miles (56 kilometres) east of Minneapolis.

The suspect was arrested about an hour and a half later while getting off the river downstream.

"Thank goodness a witness had taken a photo of him," Knudson told the Minneapolis Star Tribune.

"Another witness located him at the exit of the tubing area, where he was taken into custody."

A 17-year-old boy from Minnesota died. Two of the other victims were flown to a hospital in St. Paul, Minnesota, and two others were taken there by ambulance.

All four surviving victims – a woman and three men all believed to be in their 20s – were in critical condition.

The names of the victims and the suspect were not immediately released, but St. Croix County jail records show a 52-year-old man was being held without bond on suspicion of first-degree homicide, four counts of aggravated battery and four counts of mayhem.