CHARLES CITY, Iowa  — A 25-year-old father has been charged with killing his infant son in northern Iowa.

Floyd County court records say Shane Morris is charged with first-degree murder and child endangerment resulting in death. He was arrested Monday.

The Charles City Police Department began its investigation on Aug. 3, when the 3 1/2-month-old was taken to Floyd County Medical Center. He soon was taken to the Mayo Clinic in Rochester, where he died a day later of blunt force trauma to the head, authorities said.

A court document says Morris initially denied knowing what caused the injury. He eventually told investigators that he’d tripped while carrying his son and the boy’s head struck a kitchen counter edge. Morris also said he fell to the floor atop the child.