An autopsy confirmed that heat (hyperthermia) caused the death of two young Bradley County brothers last week.
Authorities said they would have no further comment at this time on the deaths of five-year-old Leland Bates and three-year-old brother River Bates.
Their mother, Tasha Moses, said she found the boys unresponsive at their home on Keith Valley Road. She said she drove them to their father's house because she did not have a phone.
River Bates died that day and Leland later died after being airlifted to Children's Hospital in Chattanooga.
The mother first said that drowning was involved.