A massive house fire in Missouri that killed a woman and her four children is believed to have been a murder-suicide, police said.

The fire at the home in Ferguson, Missouri, killed Bernadine Pruessner, 39, and her children Ivy Pruessner, 9; Ellie Pruessner, 9; Jackson Spader, 6; and Millie Spader, 2, according to the St. Louis County Police Department.

Police said a preliminary investigation revealed that the case was a murder-suicide and that the mother started the blaze.

“It is believed that Bernadine intentionally set a mattress on fire as that was the point of origin for the fire. A note was also left stating Bernadine’s intentions to take her life and the lives of her children,” police said in a Wednesday statement.

Police responded to a call for service at the family’s home at 4:23 a.m. Monday, the St. Louis County Police Department said in the statement. The officers were told by fire personnel that four people had been found dead inside the house and that another person was found dead shortly after. At least one dog also died in the fire, police said.

Nathan Cohen, who was Pruessner’s attorney, told NBC News she had been going through contentious custody and child support cases with the two fathers of her children.

Cohen said Pruessner, a professor at a community college, was faced “with the stress of having to be in court all the time, and trying to raise a family.”

“I think she thought these kids were being used as foils to get to her,” Cohen said.

In a statement provided by Cohen, which referred to Pruessner as Birdie, her family said “Birdie lived for her children, and focused only on their happiness.”

“Birdie got to an awful place, one that resulted in tragic consequences,” the statement said. “The family wants you to know that she got to that darkness as a result of spurious litigation and unfounded allegations by her ex-husband and her former boyfriend.”

Jared Spader, the father of Jackson and Millie, released a statement to NBC affiliate KSDK on behalf of himself and David Pruessner, the father of Ellie and Ivy, saying the fathers “have to focus on honoring the four beautiful lives.”

They did not immediately respond to a request for comment from NBC News.

“What I would want everyone to know about my two wonderful children is they are the greatest gift that a father could ever ask for,” Spader said in the statement. “Jackson was the most incredible older brother — kind, intuitive and gentle. Millie was a funny, charismatic, sweet and kind little sister who brightened every moment of every day for all of us.”

“As dads, right now we have to focus on honoring the four beautiful lives, and we plan to do that together,” the statement said. “Our thanks go out to the community, people we know and many we have never even met, who have shown us incredible amounts of support. We will continue to need it.”

Ferguson Police Chief Troy Doyle said in a statement that the tragedy has “left an indelible mark on our town.”

“Though I didn’t know them personally, their story has deeply touched not only me but also the officers who were first on the scene, and indeed, our whole community,” he said.

“It was a stark reminder of the unseen battles some of our neighbors are fighting and the critical need for empathy, compassion, and support from all of us,” he said. “This incident has profoundly affected those who served that day, showcasing the vulnerability we all share as human beings.”

This article was originally published on NBCNews.com