Erik Wiltscheck loved having a family living in the home next door in his south Minneapolis neighborhood.

The two young boys made a game of throwing balls over the 6-foot fence, knowing Wiltscheck would toss them right back over.

Wiltscheck also made a point to check in with their newly single mother, Kjersten Schladetzky, to let her know he'd lend a hand if she needed it.

He even helped shovel her driveway on Sunday morning, only to be horrified hours later when Schladetzky's ex-husband came over and fatally shot her and the boys before turning the gun on himself.

Police were called to Schladetzky's blue and white house about 10 a.m. when the shots were fired, sending the neighborhood near the American Swedish Institute into a virtual lockdown as police and SWAT teams arrived.

Wiltscheck said he was walking home from a store when he heard the two boys screaming and saw them running out the front door of the home, coats on and backpacks in hand.

"I thought it was a game. … All of a sudden, the gunshots started ringing out," he said.

It appeared Schladetzky was shot in the home, and the boys outside as they fled.

A police officer at the scene was heard telling emergency dispatch minutes after the gunshots rang out: "Dad showed up, shot the kids and went in the house."

As police officers arrived, the boys, ages 8 and 11, were lying in the front yard of the house, in the 2700 block of Oakland Avenue S.

In what Police Chief Medaria Arradondo called an act of heroism, officers ran into the open and scooped them up, not knowing if the boys were dead or injured.

"This is something that will live with them forever," police spokesman John Elder said of the officers. The boys were placed in squad cars and pronounced dead.

Police tried to make contact with someone in the house for several hours before they broke through the door. A woman's body was removed from the home and a man was found dead inside, apparently of a self-inflicted gunshot.

Elder described the case as a domestic-related homicide.

The house is in Schladetzky's name; the couple's divorce was finalized this summer.

Late into the evening, the boys' backpacks and gloves remained in the snow, leaving Wiltscheck to wonder if the brothers had been going somewhere with their father.

The boys were "full of life," he remembered. "Just dynamite kids."

Schladetzky was an intelligent, funny and gracious person, said Anna Pratt, who had worked with her at the Hennepin Theatre Trust. It was there that Kjersten met her husband, David, Pratt said.

The couple filed for divorce in November 2018 and a dissolution of marriage was granted in June 2019.

Kjersten Schladetzky was a box office manager for the Theatre Trust some years before landing a job at the American Museum of Natural History, which required her to travel to and from New York City.

"She was so excited to have her boys that it was palpable," Pratt said.

Wiltscheck saw that same excitement. She was a good mom, he said. And for her boys, "she was number one."

The neighborhood was shut down during the incident and close-by neighbors were evacuated.

At a news conference, Arradondo said the neighborhood had "faced a very sad and tragic day."

He thanked the neighbors who initially tried to help, along with the first officers who responded and the SWAT team.

"This is certainly not a conclusion that I as a chief would have wanted," he said.

Such incidents always "shock the conscience," he said. "The question is, do you ever get used to these? No, you do not."

Wiltscheck said he'll miss throwing balls over that tall fence to the two boys he was watching grow up. Every time they saw him, they'd wave hello, he said.

"If I had the chance, I would have traded my life for those kids," he said. "I just can't make sense of this."

Staff writers Paul Walsh and Libor Jany contributed to this report.