A Minnesota teenager has been killed and four others hospitalized after a Saturday stabbing attack on tubers in the Apple River in Western Wisconsin. St. Croix County Sheriff Scott Knudson says a 52-year-old man from Prior Lake, Minnesota was arrested and is in custody. No names have been released. Knudson says it isn’t known what started the incident. The 17-year-old died in a nearby hospital. The four who were seriously injured are being treated at a hospital in St. Paul. The sheriff says he doesn’t know if the attacker knew the victims.