RIVER FALLS, WIS. - Hours after Aaron Schaffhausen asked his ex-wife for an unexpected afternoon visit with their three children, all three girls lay dead in the family home and Schaffhausen was locked in a River Falls jail.

Homicide charges are expected Thursday against Schaffhausen, 34, who surrendered to police about 4:45 p.m. Tuesday. Police Chief Roger Leque described him as "non-talkative."

Authorities said Wednesday that the house on Morningside Drive was filled with gas spewing from a first-floor fireplace when police arrived, but they haven't released details of how the children died or where their bodies were found. They did, however, outline a rocky history between Schaffhausen and his ex-wife, Jessica.

The couple had divorced in January and shared legal custody of the three girls, Amara, 11; Sophie, 8; and Cecilia Lee, 5, who lived with their mother in River Falls. Police responded to a domestic disturbance report at the house in 2009, and a harassment report filed in March alleged that Aaron Schaffhaussen had called and threatened to harm one of the girls.

On Tuesday, Aaron Schaffhausen contacted his ex-wife, saying he wanted to visit the girls, Leque said. It appears the mother gave permission, and the father went to the house. A baby sitter was with the girls at the time but left when the father showed up.

Police went to the house after Jessica Schaffhausen called them, worried about a threatening text message or phone call she had received from her ex-husband.

When they arrived, police found the fireplace turned on and discovered what appeared to be flammable liquid in the basement. All three girls were dead; the Ramsey County medical examiner's office will determine how they died.

Schaffhausen, a carpenter, was fired from his most recent job last week. He was working for Solid Construction Solutions, a St. Paul firm that employed him to work on projects in western North Dakota, which is undergoing a construction boom related to a large increase in oil drilling.

“He was terminated on July 5th after not showing up for work that day,” wrote Scott Sample, the firm’s sales manager, in an email.

Seeking comfort, answers

The three deaths shocked and horrified residents of this college town about 30 miles east of St. Paul, who spent much of Wednesday searching for comfort and answers.

About 300 people gathered in Glen Park for a memorial vigil Wednesday night, and more family members and friends attended a private vigil at the Unitarian Universalist Society of River Falls, where Jessica and the girls were members.

In the park, girls in soccer uniforms who played on Amara's team gave out sheets that read, "Let's celebrate the memories and honor the girls with our voices, our silence and our ability to come together as one."

They also wrote her number 36 on their cheeks and signed messages to her on a soccer ball. As "Amazing Grace" was played, girls from the soccer team cried and hugged one another.

Ellie McGregor, whose granddaughter played with Amara, said the team decided not to participate in the playoffs this weekend because of the tragedy.

"It was an awful way to end the season," McGregor said.

She said Amara's sisters often attended her matches. "They were together. Always together, the three little girls," McGregor said, her voice cracking.

Earlier in the day, parents and children trickled into Greenwood Elementary School, where the two older girls attended classes, leaving flowers and stuffed animals.

"These girls were bright girls full of spirit," Greenwood Elementary School Principal Nate Schurman said at a news conference. "It's a terrible tragedy. We are shocked."

Amara had just finished fifth grade at Greenwood and was going to a new school for sixth grade. Sophie was going to be a third-grader at Greenwood, and Cecilia would have started kindergarten this fall.

Hundreds of people added their names to a new Facebook page created in honor of the girls. The page, "Tri-Angels -- In honor of Amara, Sophie and Cea Schaffhausen," had quickly become a vehicle for shock, condolences and practical matters such as collecting money for the family and sharing vigil information.

Aaron Schaffhausen's family joined the mourning.

"Aaron's family is deeply grieved by this terrible tragedy," his brother Eric Schaffhausen said. "We are profoundly saddened at the loss of these precious girls who we love so much. Our hearts and prayers are with all family members and friends."

Girls were mom's world

Neighbors and friends also were still reeling at the news Wednesday night and remembering the girls, who had just returned home after spending much of the summer with their maternal grandparents in Illinois.

Stefani Haar, a family friend who lives in La Crosse, said that even though Jessica Schaffhausen was younger than some of the women in their group of friends, she was the one they went to for parenting advice. "She was just real and honest."

"She endured so much during their pregnancies," Haar said. "She was just really sick but she was so happy to do it. ... She never complained because she knew what the prize was and she was so grateful. Her whole world was being a mom to those girls. ... She would have done anything to protect those girls."

Lisbeth Danielson, whose son was in Sophie's class, was at home Tuesday when officers arrived and began asking if anyone had seen Aaron Schaffhausen.

Danielson ran into her home and kept her son distracted with video games. "It's very numbing and confusing," she said. "It's very frightening.

Danielson said Amara was especially inquisitive and dreamed up experiments that she chronicled in a notebook. Once, she rigged up a string system so she could turn on her bedroom light while in bed so she could read.

"Amara was our scholar," Danielson said. "Sophie was ... she was the one, if you could find trouble, she'd find it. Cea was our princess."

Haar's memories of the girls were remarkably similar.

"Amara was smart and brilliant. She was 11 going on 30," Haar recalled. "She would cook these meals that grown women wouldn't dare take on. She was amazing.

"And Sophia was this funny, beautiful, silly kid who was so easy to love. She liked her sister's haircut better so she cut her own hair.

"And Cecilia, she was just a beautiful baby. [Jessica] made brilliant, beautiful, intelligent young women who were incredible."

The four of them went everywhere together, Haar said. "She didn't go to the store without the girls. She didn't do anything without those girls. I don't know how she is going to deal with this. Only God can help her. ... She didn't deserve this. They didn't deserve to die."

Staff writers Mary Lynn Smith, Nicole Norfleet and Larry Oakes contributed to this report. Chao Xiong • 651-735-1762