This week marks the anniversary of one of Ireland's most infamous murders and a story of sex, betrayal and intrigue. On Findmypast you can see the crumbs left by the murderer himself, read what the papers at the time said about him. You can touch the story.

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William Bourke Kirwan was an artist. By the time he married Maria Louisa Crowe in 1840 he had built a reputation as a miniaturist and as an anatomical draughtsman, providing medical sketches for some of Ireland's top anatomists. You can find his professional listing in both Pettigrew and Oulton's Dublin Almanac and General Register of Ireland for 1845 and Slater's National Commercial Directory of Ireland the following year. He even did some work for the Ordinance Survey map of Ireland.

Kirwan was a protestant, although his wife was raised a Catholic. Much was made of this mixed marriage in the press. At one point the case almost became a symbol of the religious tensions between the Catholic and Protestant communities. But the reality in Ireland at the time was far less black and white. The records reveal that Kirwan was one of many protestants to sign the William Smith O'Brien Petition which argued for clemency for a condemned Irish patriot.

On the surface William Kirwan lived a charmed life. He was a prosperous businessman, a successful artist. He had a charming and handsome wife. But behind closed doors a far darker story was playing out. Maria and William Kirwan might have seemed the perfect couple but by the summer of 1852 their marriage was in difficulty.

In 1852 Maria Kirwan had made a terrible discovery. She found out that her husband had a second family. It's not known exactly what happened when Maria confronted her husband but that summer they rented rooms in the seaside village of Howth. Their landlady would later tell the murder trial she heard violent arguments.

There's a small island just off the coast of Howth called Ireland's Eye. The Kirwan's would often take a boat across and spend the day there. William would paint and sketch and Maria would indulge in her favourite pastime, swimming.

On September 6th 1852 William Kirwan and his wife once again hired a boatman to take them across to Ireland's Eye. Other visitors saw them there during the day, one boat even offered Maria a trip back to the mainland but she refused, saying a boat would come to collect them that evening. When the boat arrived William Kirwan was standing on the shore alone. He hadn't seen his wife for hours, he told the boatman.

They searched until the darkness began to fall, then Kirwan stumbled. He waved the boatman, Patrick Nangle, ahead as he clutched his ankle. It was Nangle who made the grim discovery. Maria Kirwan's body was lying on the rocks in a cove known as the Long Hole. She was partially naked.

It took a month for suspicion to turn in Kirwan's direction. When the Dublin Metropolitan police came to arrest him, the same day Maria's body was exhumed in October, they discovered his mistress in the house on Merion Street, with some of the children.

Kirwan's trial began on December 8th. The crowds were so big the street was blocked all day. After a three day trial, reported in every newspaper, he was found guilty and sentenced to hang. The case was widely reported in the Irish, English and International Press, The New York Daily Times even carried evidence from Patrick Nangle the boatman at the trial.

Kirwan was due to hang, but on New Year's Eve 1852 his sentence was commuted to transportation. His prison record on Findmypast, describes him as a sallow, dark haired man, with grey eyes framed by dark, thick eyebrows above a straight nose. He was 5 foot 8 inches tall with a stocky build. His conduct in gaol, and in the prison camp in Bermuda he was transported to, were described as very good, although his gaolers did note disapprovingly when he was admitted that he was “supposed to be living with another woman by whom he had seven children." He made frequent petitions to be released but served a substantial sentence. He was finally released on Licence in January 1879 and went to Queenstown (or Cobh in Cork) the ideal place to board a ship to America to join his mistress.

For more than 160 years the murder at Ireland's Eye has courted controversy. There are still those who think Kirwan was treated too harshly. They think he was a victim of Victorian moral conservatism and that his wife drowned after going swimming too soon after eating. You won't find the truth about what happened that day on Ireland's Eye in the records but you will find the man, and you will find an extraordinary story.