David John Birnie was the eldest of six children. Margaret and John Birnie did their best for their kids but times were tough. For all of their young lives, the authorities periodically took the children away from their parents and placed them in government institutions. David Birnie's parents had a long history of chronic alcoholism.
At the time of the murders David Birnie's mother was living in destitute squalor. Her tiny apartment was overflowing with food scraps, dirty dishes, full ashtrays and broken furniture. The place was covered in dust and grime. She had given up hope years ago and could not recall seeing her eldest son in years. David Birnie's father died in 1986 after a long illness.
Catherine and David first met as youngsters when their families lived next door to each other. Catherine's life was also one of doom and despair. Her mother died when she was ten months old and the infant was sent to live in South Africa with her father. She was bundled back to Australia after two years and was fostered by her grandparents. A sad little girl who rarely smiled, she had no friends. Other children weren't allowed to play with her and even before she reached high school her mind was scarred by loneliness. She desperately wanted to be loved. She would find that love in David Birnie later on in her sad life. But it would drive her to a loneliness and despair that she never knew was possible.
David Birnie was reunited with Catherine when they were both in their late teens. David already had an extensive record for juvenile offences. The only time that he showed that he might make something of himself was in the early 1960s when he trained as an apprentice jockey.
But like most things in David Birnie's life, that didn't last long. Trainer Eric Parnham recalled Birnie as a pale, sickly looking boy who he took on just to give him a job. Birnie was recommended as an apprentice prospect and Parnham went to pick the boy up at his home. The house was a derelict slum surrounded by a pack of dogs. Birnie stayed in the stables for almost a year and showed enough ability to become a good jockey.
Parnham eventually sacked him when he was alleged to have bashed and robbed the elderly owner of a boarding house. Catherine found a friend in Birnie. She would do anything he desired and together they went on a crime rampage that would land them both in jail.
On 11 June 1969, David and Catherine pleaded guilty in the Perth Police Court, to eleven charges of breaking, entering and stealing goods worth nearly $3000. The court was told that Catherine was pregnant to another man. They admitted to stealing oxyacetylene equipment and using it to try to crack a safe at the Waverley drive-in theatre. Catherine was placed on probation and Birnie was sent to gaol for nine months.