Cook County’s independent inspector general has cleared employees of the medical examiner’s office of any wrongdoing in the 2015 death investigation of Chicago Police Sgt. Donald Markham.

Despite the Chicago Police Department not abiding to protocol, the inspector general’s office “found the professionalism of those [medical examiner’s office employees] involved in this case to be evident throughout this investigation.”

Patrick Blanchard, the county’s independent inspector general, noted that the police department, however, failed to notify the medical examiner’s office of the Sept. 2, 2015 death before officers removed Markham’s body from his Northwest Side home.

No investigator from the medical examiner’s office went to the scene of Markham’s death. Last week, the Cook County Board opted to change the requirement in a county ordinance that says a medical examiner’s “representative shall go to the location of the body” and begin an “investigation with an examination of the scene.”

Markham, 51, who worked in the police narcotics division, was found dead in his bed after arguing with his wife.

The police immediately treated his death as a suicide, removing the body and the bloody mattress on which it was found within three hours — even before the medical examiner’s office could examine the scene.

Within weeks, the medical examiner’s office closed the case as a suicide. However, a pathologist retained by the FBI said the death “is best certified as a homicide.”

In May 2017, Dina Markham told Sun-Times reporters she was unaware the FBI and inspector general were investigating. She drowned in her bathtub six days later, on May 28 that year, after taking pills and drinking — a death the medical examiner ruled an accident.

The FBI won’t discuss the case.

Dina Markham was working in the police department’s Bureau of Internal Affairs at the time of her husband’s death. She was transferred 11 months later to the Area North detective division, then headed by Cmdr. Kevin Duffin, whose detectives had determined Donald Markham killed himself.

After the FBI began investigating and until the day she died, Dina Markham was exchanging text messages with Duffin, the Sun-Times has reported.