Iowa infant homicide trial: 4-month-old weighed under 7 pounds at death

Iowa infant homicide trial: 4-month-old weighed under 7 pounds at death

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Sterling Koehn

Sterling Koehn, 4 months, was found dead Aug. 30. A chief Iowa medical examiner testified during his father's trial Thursday that the infant died of denial of critical care and ruled his death a homicide.

Editor's note: This article contains graphic content.

MOUNT PLEASANT -- Zachary Koehn shielded his eyes Thursday as a medical examiner walked jurors through autopsy photos of his infant son and explained how he died.

Koehn, 29, of Alta Vista, is charged with murder and child endangerment, and his trial was moved to the Henry County Courthouse in Mount Pleasant on a change of venue. The child's mother, Cheyanne Harris, is also charged and will be tried separately.

Prosecutors said medics were called to the couple's apartment around 1 p.m. Aug. 30, 2017, and found 4-month-old Sterling Koehn dead in a baby swing.

On Thursday, Dr. Dennis Klein, chief medical examiner for the state, said he determined that Sterling died of denial of critical care and ruled that his death was a homicide.

Klein went through photos that showed the condition of the baby's body as he removed layers of urine-soaked blankets and clothing that had been stuffed in the feces-stained seat. He showed where maggots had hatched on the fabric after being laid by flies attracted by the feces.


Zachary Koehn covers his face as photos of his son's autopsy are displayed during his trial Thursday.

The medical examiner said that three things were behind young Sterling's death -- malnutrition, dehydration and severe diaper dermatitis (diaper rash) with skin breakdown. Each was serious enough to individually have caused his death, Klein said.

He said he ruled out heart defects, bowel obstructions and organic brain issues.

"Nothing natural would have done this," Klein said.

Sterling had weighed just under 7 pounds at autopsy and had only gained 150 grams -- just a few ounces -- since birth.

"He should have gained pounds," Klein said. He said the child should have weighed about 11 pounds.

The soft spots on Sterling's head had sunken from dehydration, and this would have been obvious to anyone looking at the child, he said. The small size of the child's thymus -- a gland in the chest -- showed that he had been under ongoing stress.


Medical Examiner Dennis Klein testified Thursday that Sterling Koehn, 4 month, died of denial of critical care and ruled his death as a homicide.

Klein said the diaper Sterling had been wearing had been on for a "prolonged period of time," long enough for the fly eggs to hatch into maggots. He said it was likely the maggots were present while the baby was still alive.

The diaper rash caused the skin to break down, which would have allowed bodily fluids to exit and bacteria, like e.coli, to enter the body, Klein said.

The degree of rigor -- stiffness -- in the child indicated that he had died more than just a few hours before he was found, but Klein was unable to determine a time of death or even a range. He said it was possible the baby died on Aug. 30, 2017, the day he was found.

In Sterling's last days, he likely would have been lethargic, not responding to stimuli and not interacting with others, and he likely would have lost his cry, Klein said. This counters what Koehn told investigators -- that he had played with Sterling the day before and that Sterling was grabbing at his fingers, and that he heard Sterling cry around 6 a.m. on Aug. 30, hours before the 911 call.

Photos: North Iowa's mugshots of 2018


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