Nearly two years after a violent confrontation between tubers on the Apple River near Somerset, Wis., left a 17-year-old dead and four other people injured, the alleged assailant, 54-year-old Nicolae Miu, will stand trial Monday in St. Croix County Circuit Court.

He faces five felony counts and a possible life sentence in the death of Isaac Michael Schuman, the 17-year-old from Stillwater who died of stab wounds. Dozens of witnesses who had been drawn to the river on July 30, 2022, for a pleasant summer afternoon, saw the fight and its aftermath.

Miu pleaded not guilty, saying he was defending himself after his search for a missing phone led him to a group of tubers who turned on him and accused him of "looking for little girls."

The trial, which is expected to last about two weeks and will be livestreamed, will hinge on questions of self-defense, who provoked the attack, and whether Miu had the duty or even the ability to retreat. The state expects to call 44 witnesses, with an additional 21 witnesses available if needed. The trial begins Monday with jury selection. Legal experts have said the central question of the case will turn on Wisconsin's self-defense law, which allows deadly force only if "necessary to prevent imminent death or great bodily harm."

Miu told an investigator the day of the confrontation that he feared for his life after a group approached him, drew two knives, hit him and were "on top" of him.

"I thought that was it for me," Miu told Lt. Brandie Hart of the St. Croix County Sheriff's Office.

Miu told investigators that he didn't have a knife on the river, according to the criminal complaint. He said he used a knife to cut string holding his group's tubes together, but he thought he left it in his Jeep. He said the knife he used was one that he had taken from someone else during the fight.

In reviewing a video shot by witness Jawahn Cockfield, investigator Mitchell Schaeppi of the Sheriff's Office reported in the complaint that he could see a knife clipped to Miu's right pocket. Miu removed the knife, opened the blade and held it at his side, Schaeppi wrote.

A witness, Owen Lee Peloquin, also told an investigator that he saw a knife in Miu's pocket and then in Miu's hand.

The Cockfield video lasts three minutes and 20 seconds and could be shown in its entirety during the trial after Judge R. Michael Watermandenied a motion by Miu's attorneys, Corey Chirafisi and Aaron Nelson, to mute the video's final 55 seconds. They argued that the incident was over by that point, and that the raw, emotional reactions captured on the recording are unfairly prejudicial.

The state, meanwhile, argued that the video was necessary because it not only shows the fight but also the "absolute bafflement" of witnesses afterward as to what had just happened — and Miu walking away.

Judge Waterman, in a ruling earlier this month, agreed with prosecutors, saying the entire video is relevant as it shows the fatal stabbing, the panicked efforts of bystanders to help the injured after the fight, and Miu leaving the scene. The video establishes the time, place, and manner of many key events, Waterman said.

Miu has remained jailed in lieu of $1 million bond since his arrest the day of the stabbings. He was a mechanical engineer for Ritchie Engineering in Bloomington, and holds degrees in engineering and mathematics from South Dakota State University.

In his interview with Lt. Hart hours after the incident, Miu was told that four people had been injured and that one person had died.

"Oh no," Miu replied, saying later, "Oh my God. Oh God."