Death by strychnine: Poison Canadian man used went undetected for four years

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Nearly three years after Cindy MacKay’s death, her husband, 41-year-old Michael MacKay, admitted earlier this week to poisoning her.

On Monday, MacKay pleaded guilty to second-degree murder and was handed a life sentence, with no chance of parole for 10 years.

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In February 2020, MacKay dropped two of their three daughters at school before returning to their family farm in Meota, Sask. He then mixed strychnine into a drink of Gatorade and gave it to his wife.

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Cindy MacKay, 38, reported the drink tasted bitter, and didn’t finish it, but the poisoning symptoms soon set in, including painful muscle contractions and difficulty breathing.

What is strychnine?

The highly toxic, colourless pesticide is used in baits designed to kill small animals like gophers, moles and coyotes. When swallowed, inhaled or absorbed through the eyes or mouth, strychnine poisoning leads to muscle convulsions and death by asphyxia. To confirm a diagnosis of poisoning, strychnine can be detected in body fluids and tissue samples.

Cindy went into cardiac arrest shortly after consuming the substance. She was eventually taken by air ambulance to a hospital in Saskatoon, where she died from multiple organ failure.

Hospital staff became suspicious and contacted RCMP on Feb. 10, 2020. An investigation began the next day, while MacKay was removed from life support on Feb. 12.

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Michael MacKay told police and family that he believed Cindy had taken her own life. He maintained that lie for years, telling not just local community members but also immediate family, including the couple’s three daughters, who were five, eight and 10 at the time of their mother’s death.

What are the symptoms and how is strychnine poisoning treated?

The court heard that strychnine makes a person’s muscles contract intensely, and that MacKay’s death would have been very painful.

The amount of strychnine was unmeasured, but according to an agreed statement of facts, MacKay knew it was enough to be lethal.

According to clinical toxicology reports, the probable lethal oral dose in humans is 1.5 to 2 mg/kg.

There is no specific antidote for strychnine, and due to its painful symptoms, poisonings with the toxic substance have been portrayed in film and literature, including in several Agatha Christie stories.

A number of notable deaths have also been attributed to strychnine poisoning, including the death of Alexander the Great, who may have been poisoned by strychnine in contaminated wine in 323 BC. There is also a disputed theory that Delta Blues legend Robert Johnson died after drinking whiskey laced with strychnine.

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In the late 19th century and early 20th century, the substance was also used in small amounts as a “performance enhancer” for athletes, believed to be capable of boosting stamina.

Cindy’s father, Larry Mack, said he believes MacKay killed his daughter to get the farm and move on with another partner. Following Cindy’s death, the family learned MacKay had been having an affair with a woman he met online.

The court heard that he had written the woman the day before Cindy’s death, stating that “goodbye will likely be in the next few days.”

MacKay and Cindy were married on the farm in 2005. Cindy grew up there and, in 2015, she and MacKay moved there full-time.

With files from The StarPhoenix, Canadian Press.

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