The sister of Brenda Correa told ABC7 the 41-year-old Des Plaines woman and her sons, 15-year-old Leo and 13-year-old Armando, were killed by an apparent carbon monoxide leak in the family house where they were staying in Michoacán, Mexico.
Their bodies were found on July 2.
Family members said the three bodies can't be flown back to the United States because of the ongoing investigation. They are being buried in Mexico.
Brenda Correa was a teacher at the Westerhold Early Learning Center in Des Plaines.
The school district shared a letter with family members, saying "Mrs. Correa was a valued member of our ELC learning community. We are devastated by this loss as well as the loss of her children."
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A memorial service is being planned for Saturday in Des Plaines.
This is a breaking news story. Check back with ABC7 for updates.