The former wife of alleged murderer Nicolae Miu testified in court Wednesday that he's a peaceful person, saying she was worried for his safety when she saw a group of young men surround him during a 2022 Apple River tubing trip.

Sondra Miu said Nicolae had left their group to go search for a missing phone when she saw him get knocked to the ground.

"I remember seeing him in the water on his hands and knees and getting hit," she said.

The trial, in its third day Wednesday in St. Croix County Circuit Court, included testimony from more witnesses who were on the river that July 30 when Miu encountered a group of six teenage boys. Their argument quickly spiraled out of control, drawing another group of tubers into the fray. Five people were stabbed including Isaac Schuman, 17, of Stillwater, who died soon after.

Miu, who has pleaded not guilty and claimed self-defense, faces a possible life sentence.

Miu's ex-wife, Sondra, divorced him last month, though she said in court Wednesday that she still loves Miu.

Sondra Miu said she now lives in Lakeville. She and Nicolae met at their workplace, Ritchie Engineering in Bloomington, and were married in 2011, she said. They have no children.

Miu had a knife with him on the day of the stabbings because it was needed for cutting the strings that people use to connect tubes together, she testified. It wasn't uncommon for him to carry a pocketknife, she added, because Miu is handy with tools and is known as a person who often helps friends with tasks.

Sondra Miu said Nicolae had quadruple bypass surgery in 2020 and required several weeks to recover. She had warned Nicolae before they went tubing that Apple River's cold water might make it easy for rings to fall off. She said he brought a snorkel and goggles along to look for lost jewelry.

The Mius were joined by several friends and co-workers when they set out to float down the river that day. She said she didn't drink but Nicolae had maybe two beers. Nicolae Miu walked away from the group while searching for a friend's phone, Sondra testified, and that's when he encountered Schuman's group.

Miu has remained jailed in lieu of a $1 million cash bond since his arrest in 2022. The trial is expected to last two weeks. A jury of eight men and six women was chosen Monday, with two of its members to be deemed alternates. Miu has been charged with homicide, attempted homicide and battery.

In other testimony Wednesday, a man stabbed by Miu during the Apple River fight said he was certain he would die that day. A.J. Martin spent 27 days in the hospital.

The St. Paul man said a friend assured him he would be OK in the moments after the stabbing. Martin said he was left holding his own intestines after being slashed, adding: "My response was 100 percent, I'm going to die today."

Martin said he stepped into the melee in an attempt to stop the fight, and that he tried to keep Miu from standing up after he had been knocked down so that he could keep him apart from the others.

In an extended back and forth, Martin was questioned by Miu's attorney Aaron Nelson, who asked if it would have been reasonable for Miu to think he was being attacked by Martin.

"I wasn't attacking him," Martin countered. "I tried to keep him down with my arms, yes, and then I was going to tell everyone to back up and give him some space."

A woman stabbed by Miu testified that she thought she had been punched before looking down to see her torso sliced. Rhyley Mattison, 25, said Miu said nothing as the attack commenced.

"I just remember seeing [Miu's] face very blank," Mattison said. "It didn't feel real."

Mattison recalled how she had gone tubing on the Apple River to celebrate a friend's birthday. A commotion in a nearby group of tubers brought her to Miu and Schuman's group.

A video shot by Schuman's friend Jawahn Cockfield shows Mattison and her friend Madison Coen confronting Miu, telling him to leave. Miu doesn't speak while looking beyond them to where his wife and friends were located.

Several witnesses have testified that Miu struck Coen in the face, and that the fight quickly escalated at that point. After she was stabbed, Mattison said she could feel herself weakening.

"I felt like I was dying," she said.

The prosecution has argued that Miu acted criminally when he stabbed five people, killed Schuman, and then walked away as rescuers called for help and dragged the injured to shore. Miu tossed his knife in the woods before rejoining his group and floating downriver, St. Croix County District Attorney Karl Hanson said.

After he was apprehended about an hour later, Miu told St. Croix County Sheriff Scott Knudson that "I hear somebody got stabbed. … and I fit the description."

Miu initially denied having a knife with him that day, saying he was attacked by people who had two knives and that he had wrested a knife away from one of them.

Miu's defense attorneys, while agreeing to the basic facts, have argued that Miu feared for his life when 13 people confronted him, and had the legal right to self-defense. Wisconsin law allows deadly force only if "necessary to prevent imminent death or great bodily harm."