They walked, rode horses, drove carriages, even boarded the new Grand Trunk Railroad train to reach Cobourg by nine o'clock in the morning, in time to secure the best possible view of the hastily-erected gallows.

Hangings were still a rare occasion in the Province of Canada (West) and Dr. William Henry King's trip to the scaffold was the final chapter in a sensational story that made front page news right across the colony.

In every other respect, the good doctor led a virtuous life typical of 19th century values. In his final confession, he insisted with righteous indignation, "I never drank a glass of spirituous liquor in my life. I never went to a house of ill-fame in my life. I never went to a theatre but once in my life."

But Billy King, a hardworking farmer's son from Cramahe Township, exerted a magnetic appeal for the young ladies of Brighton. They flocked to Dr. King's homeopathic practice in Brighton with ailments that were rarely life-threatening and often imagined.

But Billy King liked to live in style, favouring well-tailored clothes and a well-appointed home. When the money ran out, the Kings moved to Hamilton where Billy taught school and studied medicine in the evenings while Sarah took in boarders to help make ends meet.

Sarah showed the letters to her father and the correspondence was only returned to King after he had made a formal apology to Sarah. But John Lawson's suspicions about his son-in-law were fully aroused and he kept copies of all the letters.

Billy King did eventually reconcile with Sarah in Brighton in March 1858, and in the same year qualified as a homeopathic doctor. In time he also polished up his act and was now accepted in the community as both a gentleman and a dutiful churchgoer.

King prospered in his new practice in Brighton, earning as much as $200 a month, a tidy sum for a country doctor in those days. But the more his female patients heaped attention on him, the more restless he grew.

On September 23, 1858, a pretty, flirtatious 20-year-old woman named Melinda Freeland Vandervoort walked into his life and nothing would ever be the same again.

Young Melinda decided to visit her occasional friend Sarah King but in the blink of an eyelash she was focusing all of her considerable charms on Dr. King. At the end of Melinda's lengthy visit, Dr. and Mrs. King drove Melinda home in their horse and carriage. On their return trip, Sarah King told her husband with some sarcasm, "Miss Vandervoort says she has fallen in love with you. She says she loved you before she ever saw you."

Mrs. King explained that Miss Vandervoort had seen a photograph of Dr. King at her parents' house while he was away studying medicine and had apparently fallen in love with his likeness. The rest of the journey was completed in a stony silence.

King would admit later he didn't know why his wife had "thrown Miss Vandervoort at my head", perhaps to cast her in a bad light as a flirt. If that was the plan, it backfired badly because the story of Miss Vandevoort's obsession with his photograph flattered King's vanity and made a deep impression on him.

The very next day Miss Vandervoort returned to the Kings' house and this time she stayed for the night. The beautiful Miss Vandervoort sang like a nightingale that evening as she performed several popular songs for the Kings. A serious music lover, Dr. King confessed later "her beautiful voice completely intoxicated me".

For her part, the flirtatious Miss Vandervoort was well aware the Kings' marriage was crumbling and this knowledge gave an edge to her seductive ploys.

She and Dr. King became madly infatuated with each other on that fateful night and when she returned home the next day, she sent a cameo photograph of herself and a steamy letter to Dr. King.

It read: "My heart flutters at the thought of you. Poor, little helpless me, you have an alarming influence over my girlish innocence."

A smitten Dr. King promptly wrote back a week later asking Miss Vandervoort, his "sweet little lump of good nature" if she could save herself from the marriage altar for just one year.

Those love letters a week apart would seal the fate of Dr. Billy King, because mysteriously Sarah King became very ill during that same week on October 14.

According to Dr. King, who was also Sarah's sole physician, his wife had taken ill after falling from her carriage. Later when she complained of stomach cramps and extreme nausea, Dr. King treated her for "cholera morbus" with "small doses of a white powder", causing Mrs. King to wretch violently after each dose.

Her condition worsened rapidly and when her father John Lawson insisted on a second opinion, Dr. King agreed to call in a neighbouring physician Dr. A.E. Fife. Under Fife's treatment, Mrs. King seemed to improve but as soon as he departed, she suffered a swift and irreversible relapse.

In the early hours of November 4, Mrs. King slipped into a coma and died. Her seemingly distraught husband moved quickly to have her buried on the family's land.

But Mrs. King's parents were now openly skeptical about her death. In a small town like Brighton, gossip travelled faster than a brush fire and they had already heard the whispers that Dr. King was having an affair. Sarah King's funeral was no sooner completed than they demanded a coroner's inquest.

A furious Dr. King went immediately to the Vandervoort farm in the township of Sidney where he spent an hour talking to Melinda. Then King took Melinda across the U.S. border to the safe haven of an aunt's house.

When Dr. King returned to Brighton, the inquest to his wife's death was well under way. Mrs King's body had been exhumed from its grave and taken to the local schoolhouse where two area doctors, Dr. Pelltiah Proctor and Dr. P. Gross, performed the autopsy in primitive conditions. Using an old door as an operating table, they removed her stomach for further analysis. They also discovered that Sarah King had been pregnant.

The stomach was placed in a pickle jar, sealed with wax and a one-cent coin was attached to the lid to pay for its postage. The jar was dispatched by train to Toronto and the laboratory of Henry Croft, the University of Toronto's brilliant professor of chemistry.

"The stomach was emptied into a glass of water," Professor Croft said later after his meticulous testing. "The liquid was allowed to settle, the upper part was poured off and a sediment left. This sediment was found to contain arsenic."

"I next examined the coats of the stomach and found more arsenic in them," Croft reported. "The quantity I found in the stomach was eleven grains."

Croft knew that this was five times the amount needed to kill someone and these early findings fuelled speculation that Dr. King had poisoned his wife with arsenic.

The good doctor always had supplies of arsenic on-hand for his homeopathic treatments but he later insisted that he had only given his wife minute doses as a treatment for her illness.

But Professor Croft was only interested in solid scientific evidence, not allegation or alibi. After finding the arsenic in Mrs. King's stomach, he asked the Brighton coroner Simon Davidson to send along Sarah's liver and kidneys. Croft wanted to rule out any question the stomach might have absorbed arsenic naturally when it was displayed earlier to a coroner's jury. (At that time, wallpaper contained high levels of arsenic that gave off vapours).

For the second time, Mrs. King's body was exhumed and the local doctors removed the organs, shipping them in yet another glass jar aboard the train to Toronto.

Croft's new round of tests showed only moderate traces of arsenic in Mrs. King's liver, where there should have been a considerable residue if indeed arsenic poisoning was the true cause of death.

But Dr. King didn't stay around to hear Croft's findings and fled on horseback across the U.S. border to rendezvous with Melinda Vandervoort.

His swift departure was grounds enough for an arrest warrant to be issued in Brighton. Leading the chase after Dr. King was Sarah King's brother Clinton Lawson who had been sworn in as a deputy law officer by the local authorities.

Lawson crossed the border near Kingston, met with a U.S. Marshall and together they cornered the fleeing doctor at a remote house near Cape Vincent, New York.

At this point Lawson takes up the story… "King ran towards the woods but as I was after him quick, he turned into a barn. We found him under the straw in a hog's nest. I had a revolver. I said he must be shot if he ran."

King surrendered and was brought back to a jail cell in nearby Cobourg to await trial, which did not get under way until April 4 of the following year.

On the first day of the trial, Clinton Lawson sat in the front row of the courtroom with a pistol in his pocket, having sworn to shoot King if he was acquitted.

In this tense atmosphere, King's defence lawyer John H. Cameron brought forward several witnesses to support the claim that Mrs. King was not poisoned by arsenic.

But the most dramatic moment came when Professor Henry Croft testified that he found little arsenic in the liver.

"Arsenic cannot be put into the liver after death, it must have been taken during life, that is the reason I wrote for the liver," Croft testified at the trial. "I did not determine the quantity of arsenic found in the liver. But it was very little, not sufficient to cause death."

The King trial was the first time that forensic evidence had been introduced into a court of law in Canada. But it seems the jury did not put much stock in this new-fangled science. They completely ignored Croft's expert findings and after deliberating for 19 hours, they found Dr. King guilty of poisoning his wife with arsenic.

The jury recommended mercy but trial judge Robert Easton Burns saw no reason for such maudlin sentiment and promptly sentenced King to hang. King's composure crumpled and "his lip quivered, and burying his face in his handkerchief, he wept convulsively".

"Now there was a temptation I could not resist," King said in his last journal entry. "No one else was around. She was already ill and would not survive anyway."

And so Dr. King had received the right verdict for the wrong reasons, but in the end it made little difference to the handsome doctor as he met his Maker on the hill behind the courthouse.

Yet even in the last minute of his life, Billy King seemed unrepentant about his fateful tryst with Miss Melinda Vandervoort.

"She has cost me my life, which is all any man could pay for a woman," King said "Oh! What a precious jewel. What a dear creature."