An Iowa couple has been charged with murder after their 4-month-old son was found rotting and covered in maggots.

Cheyanne Renae Harris, 20, and Zachary Paul Koehn, 28, were charged with first-degree murder and child endangerment on Wednesday, reported the Des Moines Register.

Their son, Sterling Daniel Koehn, was found dead Aug. 30 in a baby swing in their family home.

Chickasaw County sheriff's deputies and medics arrived on the scene after Koehn called 911 and requested an ambulance. Authorities found Sterling’s body in the swing, which was in a separate bedroom from where the father and an older child slept, according to criminal complaints filed in court against the couple.

An autopsy revealed "maggots in various stages of development in his clothing and on his skin," court records show.

Based on a scientific examination of the maggots, a forensic entomologist determined Sterling had not been removed from the baby swing for more than a week, nor had his diaper been changed in that time.

The State Medical Examiner ruled the death a homicide, and the cause of death was failure to provide critical care.

"The facts of this case go far beyond neglect and show circumstances manifesting an extreme indifference to human life," Chickasaw County Sheriff's Deputy Reed Palo wrote in the criminal complaints.

When deputies first arrived to the couple's apartment, Koehn reportedly told them that Harris fed the baby that morning "and he was fine." Koehn said Harris checked on the baby a couple of hours later and he had died, according to the complaints.

This story was not consistent with autopsy findings and other investigation, court records show.