July 28 (UPI) — Authorities in Michigan announced Monday that the eight family members found dead inside a burning home over the weekend died in a murder-suicide, stating the father had killed his six children and his wife before turning the weapon on himself and setting the residence ablaze.

“This is far more than a news story. This situation personally impacts dozens if not hundreds of people in the county. Our hearts go out to those families, the neighbors and co-workers, the teachers, the students of Grand Haven Public Schools and the friends of the victims,” Capt. Jake Sparks of the Ottawa County Sheriff’s Office told reporters at a press conference.

The family of eight was found dead at their Grand Haven Township home on Friday after firefighters and police were called at 11:42 a.m. EDT for smoke seen coming from the residence. Authorities initially said some appeared to have suffered gunshot wounds.

On Monday, Sparks said autopsies had been preformed, and the cause of all eight deaths was gunshot wounds. The manner of death for the mother and six children was homicide, while the father’s death was ruled a homicide.

Sparks identified the father as 47-year-old Kristopher Karolkiewicz. He identified Kristopher’s wife as Amanda Karolkiewicz, 39. He did not name the children but said four were boys, ages 15, 12, 11 and 5, and two girls females, both age 11 and adopted.

“The investigation at this point shows that this was a murder-suicide with a fire being started after the murders,” Sparks said.

“The case remains open and under investigation to try to get to the bottom and get answers of what happened leading up to the incident.”

The family’s pets, which included several dogs and at least one cat, also died from either the fire or smoke inhalation, he said.

Authorities believe that the incident may have started Thursday night and continued into Friday morning.

Sparks said there were reports of the smell of smoke in the area earlier that morning, before the fire and smoke became visible, which led to authorities being called to the scene.

The Michigan State Police, Fire Investigation Unit is working to determine the cause and origin of the fire, he said.

“Preliminary indications are that the fire was intentionally set in numerous different places throughout the residence, in the interior of the home,” he said, stating there were indications of fires being set on both the first floor and in the basement.

He also said the weapon used was a registered handgun.

Grand Haven Area Public Schools identified Amanda Karolkiewicz as a substitute teacher at Peach Plains Elementary by

“Our hearts are with their family, friends, neighbors and all who knew and loved them,” Kristin Perkowski, superintendent of the school system, said in a statement.

“Amanda, or Mandy as many of us knew her, served our students and staff with kindness, compassion and a willingness to step in wherever she was needed. She touched the lives of countless students and colleagues throughout her years with our district and will be deeply missed.”