RCMP in Grande Prairie say they hope to have some answers soon in a bizarre drugging mystery among nurses at the local hospital.

Police are now going over the results of an eight-page questionnaire that was distributed earlier this month to nursing staff at the Queen Elizabeth II hospital where at least 15 nurses may have been drugged over the past year and a half.

A questionnaire was handed-out following reports of nurses on the same surgical unit becoming ill with flu-like symptoms, extreme fatigue and memory loss.

A number of possible causes were ruled out, through air quality tests and other measures.

That led police to believe that food and drink items were being tampered with.

No new cases of drugging have been reported since police started their investigation.

The survey contained questions such as: "Did you purposely drug a nurse?", "How could a nurse become drugged?" and "What are the five top issues that could have led to this situation?"

Police say there was good compliance but wouldn't reveal how many returned the questionnaire.

Jerry Macdonald, head of the nurse's union at the hospital, said staff will be getting a break while the surgical unit is temporarily closed. He said the closure has nothing to do with the investigation and was scheduled because of summer vacation and operating room capacity.

"So they're taking advantage of that to make sure some people who get vacations and the staff who have not been sent on vacation have been sent to other units to work," he said.