David Birnie was the eldest of five children. In his formative years, he lived in the semi-rural suburb of Wattle Grove, east of Perth. School friends and parishioners from the Wattle Grove Baptist Church of the period remember the family as particularly dysfunctional. Rumours abounded about the family’s promiscuity, alcoholism and that they engaged in incest. When Birnie’s parents had asked the local priest to conduct their wedding ceremony, he expressed concerns about them as individuals and as a potential couple, broadly stating that he felt theirs was a union that could never lead to any good; an unusual and seemingly unsuited pairing, the father was a man of very small stature and unattractive appearance, while the mother was known for her coarse manner, language and behaviour, often exchanging sexual favours with taxi drivers as payment for fares. David Birnie’s school friends also commented on the family home, stating that it was unkempt and filthy, with the family never having regular meals together. Nor were meals prepared for the children by their parents. One school friend stated that the door of the Birnie fridge was always left wide open, so the children and the family dog could eat at will whenever hungry.

In the early 1960s, David Birnie’s parents decided to move the family to another Perth suburb, where he had met Catherine through mutual friends. At 15, David left school to become an apprentice jockey for Eric Parnham at a nearby Ascot racecourse. During his time there he often physically harmed the horses and developed the tendencies of an exhibitionist. On one particular night, David broke into the room of an elderly lady where he was boarding, naked with stockings over his head and attempted to commit his first rape. By the time he was an adolescent, he had been convicted of several crimes and had spent time in and out of jail for misdemeanors and felonies. As an adult, he was a known sex and pornography addict, and paraphiliac. He was married to his first wife during his early 20s and had a baby daughter. In late 1986, David Birnie was employed at a local car wreckers. For more than a year David and Catherine had practiced how to make their sexual fantasies of rape and murder come true; he was weeks away from committing his first horrific crime.

On 6 October 1986, 22-year-old student Mary Neilson turned up at the Birnie house to buy some car tires. On arrival, she was gagged, chained to the bed and raped by David Birnie while Catherine observed. She was taken to Gleneagles National Park near Albany Highway in Bedfordale and as she begged for her life, she was raped again and strangled with a nylon cord, dropping dead at David’s feet. He then stabbed her through the body, knowing that would speed up the decomposition, as he had “read that in a book somewhere”. They buried her in a shallow grave. The year after, she would have received her degree for psychology from the University of Western Australia. This murder was apparently unplanned. On 1 November, they saw 31-year-old Noelene Patterson standing beside her car on the Canning Highway; she had run out of petrol while on her way home from her job as bar manager at the Nedlands Golf Club. Once inside the car, she had a knife held to her throat, was tied up and told not to move. She was taken back to Moorhouse Street where David Birnie repeatedly raped her after she was gagged and chained to the bed. They had originally decided to murder her that same night but David Birnie kept her prisoner in the house for three days and there were signs that he had developed emotional feelings for Patterson. Quick to notice, a jealous Catherine made an ultimatum: David would have to kill Patterson or she would kill her herself. He immediately forced an overdose of sleeping pills down her throat and strangled her while she slept. They took her body to the forest but buried it away from the others. Catherine Birnie reportedly got great pleasure in throwing sand in Patterson’s face.

On 5 November, they abducted 21-year-old Denise Brown as she was waiting for a bus on Stirling Highway. She accepted a lift from the Birnies; at knife point, Brown was taken to the house in Willagee, chained to the bed and raped. The following afternoon she was taken to the Wanneroo pine plantation. Safely in the seclusion of the forest, David Birnie raped Brown in the car while the couple waited for darkness. As they dragged the woman from the car, David Birnie assaulted her again and plunged a knife into Brown’s neck while he was raping her. Convinced that the girl was dead, they dug a shallow grave and lay her body in it, but Brown sat up in the grave; David Birnie then grabbed an axe and struck her twice at full force on the skull with it before burying her body in the grave. Their final abductee and the only girl to survive their attacks was a seventeen-year-old who cannot be named for legal reasons. She ran semi-clothed and hysterical into a vacuum cleaner shop on 10 November 1986 and insisted on seeing the police. When the police arrived, she stated that she had been abducted at knife point by a couple who had taken her back to their house and raped her.

The Birnies were detained by police, who tried to trick them into confessing to the crimes by intense interrogation. Around dusk, Detective Sergeant Vince Katich said in a joking manner to David Birnie, “It’s getting dark. Best we take the shovel and dig them up.” Birnie replied, “Okay. There are four of them.” When sent to trial, David Birnie pleaded guilty to four counts of murder and one count each of abduction and rape. When asked why he pleaded guilty, he gestured toward the victims’ families and said, “It’s the least I could do.” He was sentenced to four sentences of life imprisonment. After being found sane enough to stand trial, Catherine Birnie was also sentenced to four sentences of life imprisonment by the Supreme Court of Western Australia; under law at the time, both were required to serve 20 years before being eligible for parole. Initially David Birnie was held at the maximum security Fremantle Prison, but he was soon moved to solitary confinement to keep him from coming to harm from other prisoners. The original death row cells were converted for him and he stayed there until the prison was closed in 1990. The cell can now be viewed on the Great Escape Tour held daily at Fremantle Prison. While incarcerated, the Birnies exchanged more than 2,600 letters but were not allowed any other form of contact.

David Birnie was found dead in his cell at Casuarina Prison on 7 October 2005 at 1.33am. He had committed suicide by hanging; he was due to appear in court for the rape of a fellow prisoner the next day. Catherine Birnie is imprisoned in Bandyup Women’s Prison, where she was formerly the head librarian. She was barred from attending David’s funeral; an application for parole in 2007 was rejected, and the then Attorney-General of Western Australia, Jim McGinty, said that her release was unlikely while he remained in office. Her case was to be reviewed again in January 2010; however, on 14 March 2009, new Western Australian Attorney-General Christian Porter, following requests from the victims’ families, determined she would stay in jail for life. This decision makes her the third Australian woman (after Katherine Knight and Patricia Byers) to have her papers marked “never to be released” . Her appeal of this decision was turned down in March 2010 by Porter.