Investigation into Chicago cop’s death ignored evidence possibly implicating his wife, says city watchdog, calling it ‘incompetent and incomplete’

Chicago police detectives conducted an “incompetent and incomplete” investigation into the suspicious death of an off-duty police sergeant at his Northwest Side home, ignoring evidence possibly implicating his wife, also a Chicago cop, in his death, the city’s government watchdog has concluded.

In its report made public Wednesday, Inspector General Joseph Ferguson’s office said detectives improperly removed the body of Sgt. Donald Markham, discarded a bloody mattress, failed to test his wife, Dina, for gunshot residue and didn’t bother to interview key witnesses or canvass the neighborhood.