The Lisle-Woodridge Fire Department responded to the fire in the 4700-block of Dumoulin Avenue at approximately 8:40 a.m., police said.
Authorities said the victims are two adults and four children under the age of 12.
They were identified by family as father Miguel Davalos; mother Cristina Davalos; Litzy, 12; Dylan, 5; and 3-year-old twins Melissa and Michelle.
Officials determined that the fire started in the family's Christmas tree, but the cause is still unknown. Authorities judged the home to be uninhabitable.
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