The defense team of a man on trial for the murder of his infant son has announced that they plan to call an expert on postpartum depression to testify on the man’s behalf.

The Death

In August 30, 2017, 4-month-old Sterling Koehn was found dead in his baby swing by Chickasaw County sheriff’s deputies after his father, Zachary Koehn, requested that an ambulance come to his apartment. Sterling’s body was found with maggots crawling all over him and with a diaper that hadn’t been changed in over a week. Sterling weighed less than 7 pounds.

Koehn told the responding deputies that his girlfriend had fed Sterling that morning “and he was fine.”  Harris reportedly checked on the baby a couple hours later and found that he had died.

An autopsy of the body showed “maggots in various stages of development in his clothing and on his skin.” A forensic entomologist examined the maggots and concluded that Sterling had not been removed from the baby swing in more than a week and had not had a diaper change or bath during that time. The Iowa state medical examiner ruled the death was a homicide and the cause of death was failure to provide critical care.

Sterling’s parents, Zachary Koehn, 28, and Cheyanne Harris, 20, were charged with first-degree murder and child endangerment.  Koehn and Harris are being tried separately.

Murder trial of Zachary Paul Koehn

Koehn’s defense team retained an expert on postpartum depression to testify as an expert witness. Postpartum depressions can cause debilitating anxiety, depression, and fatigue in new mothers. The prosecutor on the case, Assistant Iowa Attorney General Denise Timmins, asked the court to disallow any evidence of Harris’ mental health.

Public Defender Steven Drahozal said, “The mental health status of that parent, we think, is extremely important to whether or not Mr. Koehn denied care to the child. … This is relevant to whether Mr. Koehn acted appropriately and willingly in denying care to his child and whether he was inquiring and what information he was being given, who the primary caretaker was, what kind of care was being given.”

Drahozal intends to argue that Koehn believed that Harris was caring for the infant, but that she wasn’t because of postpartum depression. Koehn’s defense team also subpoenaed Harris to testify, but her attorney, Aaron Hawbaker, invoked her Fifth Amendment right against self-incrimination.

Hawbaker said, “Nobody from the state or the defense can call her simply to take the stand and assert the Fifth, so we are asserting her right against self-incrimination.”

Koehn’s defense team is also seeking to exclude some of the photos of Sterling’s remains, arguing that the photographs are gruesome and don’t go to prove the nature of the death. Drahozal said that the medical examiner and sheriff’s deputies could testify about the condition of the body and cause of death without using the photos. The prosecution has argued that the images are important to answering questions about the time and manner of Sterling’s death.