Fire personnel who responded to a Michigan house fire found eight people, including six children, dead inside the residence, some with gunshot wounds, authorities said Friday.

Ottawa County Sheriff’s Office Capt. Jake Sparks called the scene “complicated” and “complex” amid the ongoing investigation into the deaths.

The incident occurred Friday in Grand Haven Township, located on Lake Michigan west of Grand Rapids.

Fire personnel initially responded to the area Friday morning following reports of the smell of smoke, though they were unable to locate a house fire, according to Sparks.

Several hours later, fire crews returned to the area following calls of white smoke at a residence and went inside the home to battle a fire, Sparks said.

“When they got inside, they noticed that there was several, numerous people deceased inside the home,” Sparks told reporters.

Eight people in total were found inside, including six children believed to be between the ages of 5 and 15, according to Sparks, who said not all have been positively identified yet.

Two adults were also found dead inside the residence, he said.

All those found dead are believed to be from one family, Sparks said.

Some of the victims had gunshot wounds, according to Sparks, who said it is unclear how many people had been shot.

The causes of death have yet to be determined, he said. The autopsies are expected to be completed over the weekend.

Investigators are considering the possibility that the fire was set intentionally, and that this could be a murder-suicide, Sparks said, though stressed it is early in the investigation.

Authorities are not considering any suspects from outside the home at this time, he said, noting that that could also change.

“I don’t want to jump to any conclusions at this point,” Sparks said. 

Arson investigators from Michigan State Police are assisting at the scene, Sparks said. The fire is believed to have started inside the home, though the exact origin and cause remain under investigation, he said.