A 54-year-old Minnesota man was convicted Thursday in the slaying of a high school student and stabbing of four other people who were tubing on a western Wisconsin river.

A Wisconsin circuit court jury found Nicolae Miu guilty of first-degree reckless homicide, four counts of first-degree recklessly endangering safety and one count of battery, Minnesota Public Radio reported. No sentencing date has been set.

Isaac Schuman, 17, of Stillwater, Minnesota, was stabbed to death in late July 2022 while he and the other victims were tubing along the Apple River in St. Croix County, which sits along Wisconsin’s state line with Minnesota.

Two men from Luck, Wisconsin, a woman from Burnsville, Minnesota, and a man from Elk River, Minnesota, were wounded.

Miu, of Prior Lake, Minnesota, attacked the group after people accused him of approaching children in the water, investigators said in court documents. Miu told investigators that he acted in self-defense.

Miu was tubing down the river with his wife and several other people, according to a copy of a criminal complaint obtained by Minnesota Public Radio.

Miu told investigators that he was using a snorkel and goggles to look for a lost cellphone. Video and witness accounts indicate bystanders accused him of approaching children in the water. Witnesses said Miu was bothering a group of juveniles and others told him to leave, the complaint stated.

Instead of leaving, Miu punched a woman and a fight ensued, according to the complaint. Video shows him falling into the river, emerging with a knife and then stabbing a person.

Miu told investigators that he was provoked, according to the complaint. “They attacked me,” he said. “I was in self-defense mode.”

Prosecutors had argued that Miu had opportunities to diffuse the situation or walk away.

Defense attorney Aaron Nelson told reporters Thursday that he was surprised and “respectfully disappointed” by the verdict. Nelson said Miu was “sad, obviously disappointed in the result. And, you know, contemplating his future life.”

Schuman was heading into his senior year at Stillwater High School when he was killed. His family described him as an honor roll student who was preparing to apply to several universities to study electrical engineering.