When Helen Ryan was told her husband Jeffrey had been found shot dead at their bush property, she was inconsolable. She sobbed and screamed hysterically as the neighbour who’d discovered the body tried to comfort her. Helen begged her neighbour not to let ambulance officers take her husband away until she said goodbye. “It wasn’t meant to be this way,” she wept. Ten days later, at the funeral, the hearts of family and friends went out to the pale widow in black.

When she later tearfully faced TV cameras for the police, side-by-side with her husband’s mother, Marie, to appeal to the public for information about the devastating murder, the community commended her for her courage. Two years on, that 51-year-old grief-stricken widow is revealed to have been the killer herself, persuading her younger sister to help her recruit a hitman, and their elderly mother, Coralie Coulter, to put in thousands towards the $30,000 fee for the contract execution.

Ryan “deliberately and methodically plotted to have her husband killed,” said NSW Supreme Court Justice Megan Latham in October last year as she sentenced her to 36 years’ jail. Jeffrey, it turned out, had ended their 15-year relationship and cut her stake in his will, which included a million-dollar farm at Duri, near Tamworth, NSW, so she’d “embarked on a cold-blooded plan to get rid of her husband” rather than lose a share of his money. Nerida Campbell, curator at Sydney’s Justice & Police Museum, who put together the recent Femme Fatale exhibition, says fiendish females can sicken us more than their male counterparts.

“Society doesn’t perceive women as being violent or criminal so when they are, it’s very shocking for us,” she says. “We think of women as mothers and carers and nurturers and supporters, not as people who hurt. That’s where the shock value lies even more.” Yet we have always had a fascination with flawed females – from Eve who brought about man’s downfall, and the witches of Sleeping Beauty and Hansel And Gretel, to those in modern fables, such as Sharon Stone’s Basic Instinct character stabbing men to death with an ice pick, and Glenn Close’s bunny-boiler in Fatal Attraction.

Read more crime stories in this week's Woman's Day, on sale January 2, 2012.