Story highlights A stepson says the man shot his mother, brother and sister

The man was found dead at the scene of undetermined causes

Robbins, Illinois, is about 20 miles south-southwest of Chicago

Police in the metropolitan Chicago village of Robbins, Illinois, said they are investigating an incident in which a man is believed to have shot and killed his wife and two of her children before also dying.

A third child told Robbins police that his stepfather shot his mother, brother and sister. The suspect, Michael Worsham, was found dead in the home where the shootings took place late Sunday. Police said the cause of death was undetermined. The three others all suffered gunshot wounds, according to police.

The 14-year-old boy also said he attempted to wrestle the gun away from his stepfather, who told him he could leave if he stopped fighting. The teen then grabbed his 5-year-old nephew and ran to a friend's house.

Robbins is in Cook County, about 20 miles south-southwest of downtown Chicago.