Eloise Worledge was eight when she was taken from what should have been the safety of her own bedroom in a bayside family suburban home. A torn flywire screen and an open window were the main clues in a crime that became an iconic moment: the child kidnap case that made Melbourne families lock their doors and wonder about strangers in the street.

Despite the biggest missing-person's search in Victoria's history and despite a $10,000 reward posted in 1976 that remains unclaimed, no trace of her has ever been found.

The photograph of the smiling little blonde girl remains haunting. When homicide cold-case detectives began reinvestigating the case in 2001, they were surprised to discover the picture of Eloise was instantly recognisable, more than 25 years after her disappearance. The picture of her bedroom, hung with her artwork from school and favourite pin-ups, still conjures a sense of stolen innocence.

But other images from that case have not stood the test of time. Eloise was meant to have come from a happy family and to have disappeared on a quiet, uneventful night. In fact, at the time of her kidnap, her parents were so bitterly estranged her mother at times wondered whether Eloise had been taken by her father; she hoped this meant her daughter was safe and would be coming home. In contrast to the image of a sleeping, middle-class suburb, witnesses later reported more than 200 suspicious incidents in the area on the night she disappeared.

As for the torn flywire that so frightened Melbourne parents - it could, police concluded, have been a red herring. In January 1976, Gough Whitlam had only weeks earlier been voted from office. A lingering, easy liberalism pervaded Australian life, but in suburbs like Beaumaris, couples like Patsy and Lindsay Worledge found a conservative sanctuary. Married just over 10 years and with three healthy and happy children, they appeared the perfect family. But the marriage was on the verge of collapse.

Patricia Ann Watmuff was a student teacher when she met her future husband. New Zealand-born Lindsay was three years older and building an academic career. Eloise was their first child, born on October 8, 1967. She was followed by Anna two years later and Blake in 1971.

By the time Eloise was born, the couple had settled into a four-bedroom weatherboard home in Scott Street on the corner of Gibbs Street, about 500 metres from popular Beaumaris beach. Little traffic passed through Scott Street. It was an Australian dream realised - an affordable home by the sea, with an outdoor lifestyle close to shops, schools and work. But above all else, it was safe; so safe many people still felt you could leave doors unlocked.

The area filled with young, middle-class families with similar aspirations. Soon the couple built an extensive friendship network in the surrounding streets. Their children played together and families grew close in a relaxed atmosphere.

Eloise went to the Beaumaris Primary School, just two streets away, and was due to start grade four. She was shy but intelligent and like her mother - a qualified arts and craft teacher - exhibited a creative flair. She was becoming more confident through Brownies, and her interest in art was encouraged by her parents and a local group called the Hubble Bubble Club. Patsy was well-liked. She was energetic and enthusiastic, the sort of person who attracted friends. Lindsay was introverted and bookish. He was clever and, according to some, did not mind letting people know it. "He was often described as thinking of himself as intellectually superior," a police review of the case found. After a decade of marriage, the Worledges found they were drifting apart.

Patsy immersed herself in her children, local friends and her passions for art and craft. Lindsay spent more time at the Caulfield Institute of Technology, where he was a lecturer, and completing his masters in business administration at Monash University. Soon the marital tensions became obvious, including to Eloise. Friends noticed Lindsay's comments to his wife becoming increasingly sarcastic. Some became uncomfortable in his presence and felt he was damaging the vibrant Patsy's self-esteem.

She thought they should try counselling, a move her husband refused. But Patsy went ahead alone and, while it did not improve their marriage, it helped her come to terms with the crumbling relationship. She found she was able to cope with her husband's barbs and pursued her own interests which, according to police, "only increased Lindsay Worledge's resentment towards her". By 1975, their relationship was in free-fall and they began to build independent lives. As their marriage was dying, both found comfort with others. Their personal troubles would have remained private if their tragedy had not been so public.

In September 1975, four months before Eloise's abduction, Patsy started talking of a separation. Lindsay agreed in principle, but in practice tried to delay the inevitable.