ALTA VISTA, Iowa – Neighbors of the little boy found dead in a baby swing say they heard about his August death but that details were "hush hush," reports CBS affiliate KIMT.

According to court documents, Zachary Koehn, 28, called 911 on the morning of August 30 requesting an ambulance. Koehn told the dispatcher that his girlfriend, Cheyanne Harris, 20, had fed 4-month-old Sterling at 9 a.m., and he was fine. He then said she checked on the boy again at 11 or 11:30 a.m and he had died.

But a medical examiner's report disputes Koehn's account, finding that Sterling's body had maggots in various states of development on his clothing and skin, indicating that the child hadn't had a diaper change or been removed from the powered swing in the apartment in over a week. He weighed less than seven pounds at the time of his autopsy.

Get Breaking News Delivered to Your Inbox

"The facts of this case go far beyond neglect and show circumstances manifesting an extreme indifference to human life," reads the criminal complaint.

The Des Moines Register reports that Sterling's body was found in a bedroom separate from the one the couple and an older child slept in. According to the Chickasaw County Sheriff's Office, the older child is "safe."

The newspaper also reports that court records state Koehn and Harris have a history of methamphetamine use, but no run-ins with local law enforcement or criminal convictions in the state of Iowa.

Neighbor Misty Bergmann told KIMT that she heard about baby Sterling's death in August but no one seemed to have details.

"We kind of heard right away that something had happened over there but everything was real hush-hush," Bergmann said.

Koehn and Harris have both been charged with murder and child endangerment resulting in death. They are both being held on $100,000 cash-only bond.

Chickasaw County Sheriff's Office told CBS News' Crimesider they were unable to provide information about why it took nearly two months for charges to be brought against the couple.