Heather Jensen, 24, was arrested two weeks ago in Florida and charged on suspicion of child abuse resulting in death, criminally negligent homicide and false reporting to authorities, The Denver Post reported.
Court records state that Jensen allegedly left her who sons, William, 2, and Tyler, 4, locked in a heated car for 65 minutes in November while she had sex and smoked marijuana in a nearby truck.
Both boys suffered heat stoke. William died at the scene and Tyler died a week later at Children's Hospital in Denver.
People who knew Jensen said they witnessed her neglecting the boys, but never notified the Mesa County Department of Social Services to express concern.
"I am at fault. We are all at fault. Those boys would be alive today if we had done something," Heidi Raffaelli, an aunt of the boys, posted on a Facebook page dedicated to venting remorse over the boys' deaths.
"She deserves everything she has coming to her," Raffaelli said. "Those boys were neglected. She couldn't take care of them."