(CNN) -- A father returned to his central Michigan home late Monday to find his wife and two sons dead, police say, and the horrific scene shows the signs of a murder-suicide.
The mother, in her 30s, was found dead, along with her two preteen sons, and police say that she may have killed her sons before killing herself.
But police are still investigating and awaiting an autopsy report, which they say will hold more clues to what happened inside the family home in Eaton County near Lansing.
It is unclear why the mother would have killed her children, police have said.
Police are not releasing the names of the victims until their next of kin are notified. They also refused to disclose any other details such as the father's and mother's occupations.
Investigators questioned the father, who called police about 5:20 p.m. He stumbled upon the scene, police say, when he walked into his apartment at Plum Tree Apartments in the Waverly area of Delta Township just west of Lansing. Police say he is shaken over the loss of his family and is meeting with a victim's advocate.
"Several hours after the incident, he was still being questioned and being cared for because he was very distraught also," said Eaton County Sheriff Mike Raines. "Understandably so; he's having a very difficult time."
In his 18 years on the force, Lt. Jeff Warder of the Eaton County Sheriff's Office said he has never had a mother-child murder-suicide case.
"It's obviously a tragic situation, and we want closure for everybody as soon as possible," Warder said.
Investigators expect to have more substantial details on the case by the end of the week, Warder said.