Friends tubing with Nicolae Miu on the day he's accused of slashing five people during a confrontation on Wisconsin's Apple River said he was shocked and silent afterward.

Their testimony Friday began day five of Miu's trial in St. Croix County Circuit Court, where the proceedings are expected to continue into next week.

Witnesses have shared gruesome details about the stabbings, including those surrounding the chaos that accompanied rescue efforts and witnesses' struggle to document what happened.

Prosecutors charged Miu with intentional homicide and four counts of attempted intentional homicide in connection with the July 2022 incident that left 17-year-old Isaac Schuman dead and others seriously injured. He could face a life sentence.

Miu's attorneys have argued that their client feared for his life and had the legal right to self-defense, and on Friday, called Ernesto Torres-Chaguez to testify to that.

Torres-Chaguez said he asked his best friend of 10 years to bring a pocket knife that day to cut twine used to hold their inner tubes together. He said he doubted Miu would ever try to harm someone.

Gilma Constanza testified that she was in the group tubing with Miu. She said she told police that she saw Miu toss something toward the riverbank after the fight and that he appeared scared when he returned.

Authorities recovered from the riverbank a pocket knife that may have been used in the assault.

At least 10 people were in Miu's group, and they drifted close to Schuman's group as they searched for a friend's lost cellphone. Some of them had abandoned the search because they figured insurance would pay for the phone. But Miu, who reportedly brought a snorkel and goggles to look for any jewelry lost in the river, kept searching.

The missing phone belonged to Ariel Chaguez, who was near the fight. Chaguez thought Schuman's group was bullying Miu before a blond woman in a black swimsuit yelled at him to leave. He said Miu defended himself from the woman but could not remember many details of what happened afterward as the confrontation escalated quickly.

"I remember that he fell to the water ... I think that somebody was pushing him down," Chaguez testified Friday, adding that Miu defended himself from a woman who tried to hit him.

"When we started walking back ... on the other side of the river was the young man with the injury to his stomach. He was shouting, 'Look what you did to me.' He was yelling and shouting at Nic. And at that moment, the young guy fell to the water."

Days after the stabbing, Sergio Ruiz-Leyva said he was part of Miu's group. Ruiz-Leyva told police that Schuman's group surrounded Miu as the blond woman in a black swimsuit told Miu to leave.

"Nic went up and pushed her," Ruiz-Leyva said, according to interview transcripts read aloud Friday in court.

Ruiz-Leyva said he didn't recall much of what happened afterward but said Miu and others sat in silence. When they asked what happened, Miu told them: "They had taken the knife away."

Torres-Chaguez reportedly told police 17 times that someone took a knife from Miu, but said he didn't remember when prosecutors asked.

"We didn't talk about anything else," Ruiz-Leyva said, adding that Miu donned the hat, jacket and sunglasses he wore before entering the river. "[Miu] looked pale when he got to us. His eyes wide open — he just sat there and didn't talk anymore."

He said he did not recall seeing injuries on Miu.

Further testimony suggests that Miu's group stayed "for a long time" after the incident to try to help the injured.

Miu was arrested an hour later near the spot where tubers typically exit the river, telling St. Croix County Sheriff Scott Knudson that he heard, "Somebody got stabbed … and I fit the description."

Members of Schuman's tubing group said the confrontation began when Miu mentioned "looking for little girls," but that was not shown on video played during the trial.

Star Tribune staff writer Matt McKinney contributed to this story.