UPDATED 10:30 PM EDT Jun 15, 2013

A North Carolina medical examiner knew carbon monoxide killed a couple in a Boone motel a week before an 11-year-old boy died in the same room.

The Charlotte Observer reported Saturday that Watauga County medical examiner Dr. Brent Hall resigned Friday.

Toxicology tests completed June 1 by the Office of the State Medical Examiner showed lethal levels of carbon monoxide in the blood of 72-year-old Shirley Mae Jenkins, who was found dead with her husband on April 16 in Room 225 at the Best Western Plus Blue Ridge Plaza.

Hall failed to share those results with local health officials.

Jeffrey Williams of Rock Hill, S.C., died in Room 225 the following week. Investigators determined an improperly ventilated pool heater located a floor below the room was the source of the gas.