OTTAWA -- Ontario Provincial Police say the investigation into several suspicious deaths at the Hawkesbury and District General Hospital could take several months.

Dr. Brian Nadler, 35, has been charged with one-count of first-degree murder. Nadler appeared in court on Tuesday, and the case was adjourned for two weeks.

On March 25, Hawkesbury OPP officers were called to the Hawkesbury and District General Hospital. Albert Poidinger, 89, of Pointe-Claire, Quebec was pronounced dead at the scene and Nadler was taken into custody.

In an update on the investigation Thursday morning, the OPP said while post-mortem examinations have been completed, analysis and toxicology reports from the Office of the Chief Coroner and the Ontario Forensic Pathology Service could take months.

Police have not said how many suspicious deaths are under investigation.

The OPP has held virtual meetings to ensure family members understand the procedures being followed during the investigation and the roles of those involved in the case.

Nadler's lawyer says his client maintains his innocence.

Anyone with information regarding the investigation is asked to contact the Hawkesbury OPP at 1-888-310-1122.

Hawkesbury is about 100 kilometres east of Ottawa, near the border with Quebec. 

With files from The Canadian Press