Police Chief Joseph Petruch said it's likely the family died Saturday, but their bodies weren't discovered until Wednesday after a family member called police for a well-being check, WMAQ-TV, Chicago, reported Thursday.
The dead were identified as Micheal Nichols, 41, Kennetha Purnell, 38, Matthew Nichols, 13, and Morgan Nichols, 11, The Times of Northwest Indiana reported.
The family had just moved into the home and didn't yet have power. They were using a gas generator, which was found in the garage, WBBM-TV, Chicago, reported.
Police said the generator is believed the cause of the carbon monoxide poisoning.
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