The Calling by Inger Ash Wolfe

Sixty-one year old DI Hazel Micallef lives with her mother in the small town of Port Dundas, a few hours north of Toronto. Hampered by a bad back that might need surgery and a fondness for alcohol, she is also still smarting from the breakup three years ago of her almost forty-year marriage. Then Hazel's problems take a back seat when a local woman is found murdered at home. Hazel and her team are able to connect the death with a crime in Ottawa. It appears that someone is going across Canada as a sort of angel of death, killing people who are terminally ill in a brutal way. The police always seem to be a few steps behind the man they dub "Belladonna." Will they be able to catch up with the killer and put an end to his gruesome journey? For readers who enjoy police procedurals that are leisurely paced. It has an almost British/Scandavian mystery feel.