Four people found dead in home by distraught relative

The man, named as Cory by Nine News and described as a family member and a neighbour, said he went to the home and knocked on the door but no one answered.

He claims to have looked in a window to see a 17-year-old boy lying on the floor. It's believed a woman and two men were also inside the home.

"I've come home to find family members in the house deceased and it just tortured me, shocked me," he told Nine's Today program.

"I think (it was) an overdose but I'm not too sure exactly."

Victoria Police were called to the home before 2am on Tuesday and an investigation is underway.

A police spokesperson said the cause of death was yet to be determined but at this stage the deaths are not believed to be suspicious.