Mesa County coroner's officials say two boys who were found unconscious after they were left in their mother's SUV in November died of hyperthermia, or overheating.
Coroner's officials said Tuesday that the deaths of 2-year-old William Jensen and 4-year-old Tyler Jensen were ruled accidental.
The Daily Sentinel reports that according to a search warrant affidavit, the boys' mother, Heather Jensen, called 911 on Nov. 27 and said William had no pulse, while Tyler was "gurgling" with every breath.
William died at the scene. Tyler died later at a hospital in Aurora.
The affidavit says Heather Jensen allegedly told investigators that after the boys played in snow near Powderhorn Ski Resort, she left them in her SUV with the engine running while she met with a male friend.