MOUNT PLEASANT, Iowa -- A prosecutor in the trial of an Iowa father whose infant son was found dead and maggot-infested in a baby swing last year has told a jury the child "died of diaper rash."Assistant Iowa Attorney General Coleman McAllister told jurors Tuesday that 4-month-old Sterling Koehn had been in the same diaper for nine to 14 days when his body was found in the swing Aug. 30, 2017, at his parents' Alta Vista apartment, the Courier reported .The baby's father, 29-year-old Zachary Paul Koehn, is charged with murder and child endangerment. The boy's mother, Cheyanne Harris, is also charged and faces a separate trial at a later date.McAllister said Tuesday in opening statements that the baby's heavily soiled diaper had attracted bugs that had laid eggs, which had hatched into maggots. The resulting diaper rash led to ruptured skin, and e.Coli bacteria set in."He died of diaper rash. That's right, diaper rash," McAllister said.A coroner's report showed the baby died of malnutrition, dehydration and the infection.In opening statements Tuesday, Koehn's attorney said the baby's death was a tragedy, but not a crime.McAllister denied the defense's claims, saying Koehn was an experienced parent. He noted that Koehn's 2-year-old daughter was also in the apartment and was healthy, and that Koehn had money to buy food and baby supplies. He stated Koehn was a drug user.Nurse and county rescue squad EMT Toni Friedrich testified Tuesday that she was the first to arrive at the apartment after Koehn called 911 to report the baby had died. Friedrich said Koehn showed no emotion when he led her to the dark, hot bedroom where the baby's body was.The baby's "eyes were open, and it was a blank stare," she said.Friedrich said when she touched the baby's chest, his clothing was crusty. When she moved his blanket, gnats flew up, she said.Koehn's trial was moved from Chickasaw County to Henry County to counter pretrial publicity.