A Scent of Almond - Richard Whitten Barnes

When Ontario Detective Andrea Blake investigates the newly discovered corpse of a man missing for two years, she gets way more than she bargains for: serial poisonings!
A serial killer at large.
Detective Andy Blake's life couldn't have been better. Her love life with Grant Stacey is on track, and she is happy in her new job with the Ontario Provincial Police. But her tranquil life on beautiful St. Joseph Island is interrupted with a simple request to take over the investigation of a two year old poisoning death.
The routine case turns complicated when curiously similar unsolved deaths are discovered over a period of several years, and cyanide is a common thread. Adding to the turmoil is Dan Graves, a renaissance man if there ever was one, and a contender for Andy's affections. She finds herself pulled in all directions before coming to grips with the A Scent of Almond.