More details emerge in Alta Vista child’s death

By James Grob, news@nhtrib.com, New Hampton Tribune

Charges in the death of a 4-month-old Alta Vista boy came about two months after the child was found dead, because authorities were building the case and waiting on scientific and medical tests, the Chickasaw County sheriff said.

Sheriff Marty Hemann discussed the case of an Alta Vista couple charged with murder  at a meeting of the Chickasaw County Board of Supervisors this week.

The case, which has attracted national attention, is still under investigation, Hemann said, so he couldn’t go into much detail.

But he did address a question he said he has heard in the days since first-degree murder charges were filed against Zach Koehn, 28, and Cheyanne Harris, 20.

Why did it take two months to file charges?

“We always need to be thorough in our investigation,” said Hemann. “We have to make sure we are fact-based, not emotional, when we file charges.”

Four-month old Sterling Koehn, the child of Zach Koehn and Cheyanne Harris, was found dead in a powered swing seat in a bedroom at their Alta Vista apartment on the afternoon of Aug. 30.

Chickasaw County sheriff’s deputies arrested Koehn and Harris on charges of first-degree murder and child endangerment causing death on Wednesday, Oct. 25.

Hemann said the Sheriff’s Department was working with the Iowa Division of Criminal Investigation, and a lot of scientific and other investigative research needed to be completed by all parties before they could be certain they had an air-tight case.

“We have to have all of our ducks in a row,” Hemann said. “Our people need to bounce things off the DCI, and we needed make sure we were on the same page as the prosecutors. We took our time. We have to build a case before we file charges.”

An autopsy was done at the Iowa State Medical Examiner’s office in Ankeny, and the death was ruled to be a homicide. The official cause of death was failure to provide critical care.

Chickasaw County Sheriff’s Chief Deputy Reed Palo wrote in the criminal complaints, “The facts of this case go far beyond death and show circumstances manifesting indifference to human life.”

At the time of his death, Sterling weighed less than 7 pounds and was 14 inches in length, the report said. That put him well below the bottom 5 percent of weight and height for babies that age.

Harris and Koehn both said they had checked on Sterling the day before, but their claims were inconsistent with autopsy results and other findings from the scene, court documents state.

When Koehn made the initial 911 call just before 1 that afternoon, he said then that the child had been checked and fed between 9 and 9:30 that morning, and had been discovered unresponsive around 11 a.m.

That story was also inconsistent with the evidence found during the investigation, authorities say.

The child’s body and clothing contained maggots, the report said, and their stages of development were used to help come up with a timeline for the child’s death.

A forensic entomologist (an expert on insects) “indicated that the child had not had a diaper change, bath or been removed from the seat in over a week,” court records show.

According to reports on social media, Koehn and Harris surrendered their cellphones to authorities the day the body was found.

Another young child, a 2-year-old daughter, living in the 304 East Wilson Street Alta Vista apartment, was immediately removed from the couple’s guardianship, although Harris and Koehn were allowed supervised visits until their arrests.

On the evening after the infant’s body was discovered by authorities, the two stayed in a New Hampton hotel, according to Koehn’s social media posts, as they were not allowed into the apartment, apparently because it was a crime scene.

Harris was picked up by police Wednesday, Oct. 25, in Riceville, the day after charges were filed. Koehn was arrested in Charles City, where he had recently started a job as a truck driver.

Koehn is currently being held in the Chickasaw County jail and Harris is in Bremer County, under $100,000 cash-only bonds.

Reports filed in connection with the arrests indicated Koehn was in substance abuse treatment and reportedly last used methamphetamine in August.

The reports came from the Iowa Department of Correctional Services.

Harris, who had told officials she was being treated for post traumatic stress disorder, was also in treatment, and her last known use of methamphetamine was in early October.

In a social media post in mid-October, the two proclaimed they were “clean.”

Neither of the two have prior criminal records, although Koehn was arrested for theft in 2016 for bypassing a Riceville water meter after water service was cut off to his home.

The charge was dismissed when he agreed to pay about $1,600 in restitution and court costs, but in August prosecutors sought a contempt hearing because he hadn’t made payments in several months.

An arraignment for Koehn and Harris on the murder and child endangerment charges is scheduled for 9 a.m. Wednesday, Nov. 14, in Chickasaw County District Court.

Conviction of first-degree murder in Iowa requires a mandatory sentence of life in prison without the possibility of parole.