Ciara Glennon was born in a bush hospital in Zambia 29 years ago when her Irish parents, Denis and Una, moved to Africa to take up teaching posts in the region. Two years ago next month she went missing from her home in Perth, Western Australia and three weeks later her body was found in bush land, 50 km north of the country's third largest city.

Her murder, at the hands of a serial killer who is believed to have murdered three young women, stunned the local community and the whole state of Western Australia mourned her death.

The Glennons went to Africa from Mayo and Monaghan and settled in Australia when Ciara was five years old. She was a bright, fun-loving, adventurous child. She gained a law degree, mastered Japanese at the University of Western Australia and had no problem securing a job with a successful local law firm.

Irrepressibly free-spirited, at the age of 26 she took a one-year career break to travel the world. During this time she visited Israel, Greece and Turkey and spent six weeks, longer than she had intended, with relatives in Ireland. In late February 1997 she returned to Perth for the wedding of her sister Denise. Her wanderlust sated, she got her old job back as a solicitor and was put in charge of a case that would have taken up most of the following two years.

She was wearing a claddagh brooch on the single-breasted jacket of her black suit when she went with colleagues for drinks at the Continental Hotel in the upmarket suburb of Claremont on the evening of Friday, March 14th. She was slim and brighteyed, with dark brown curly hair that fell past her shoulders. There was only one week until her sister's wedding, and the night was something of an early St Patrick's Day celebration. At around midnight, she left the hotel to get a taxi, anxious not to miss an early appointment the next morning. She was 10 minutes from her home.

Denis Glennon sits in the boardroom of Western Australian Environmental Protection Authority (EPA) where he has just finished a board meeting. As managing director of Environmental Solutions International, a waste processing and disposal company, he was recently appointed to the board of the EPA. In fact, but for this interruption to his schedule he would be next door with his fellow board-members, talking shop over a glass of wine.

He seems uncomfortable and understandably wary of talking to the media. His treatment at the hands of some Irish newspapers (not The Irish Times) at the time of Ciara's disappearance resulted in a written apology to him and his family.

He is well spoken, impeccably dressed. He carries a compact mobile phone and wears a wider than usual marriage band on his wedding finger. Behind him the Swan River sparkles soothingly under a clear Perth sky as he waits for the interview to begin.

When he speaks it is in the carefully measured tones of those who have suffered too much to bother wasting words. Instead of choosing to assert Ciara's personality, her talents, her essence, he phones his secretary and instructs her gently, in his still distinctly Irish accent, to fax over the eulogy he wrote for her funeral Mass. It talks more eloquently than perhaps he ever could again about who his daughter was.

Instead of answering questions about how the investigation into his daughter's death is progressing he punches numbers into his phone and calls the head of the police task force set up to catch the Claremont serial killer. He knows that without his say-so the police are unlikely to co-operate with an out-of-town journalist. "You should be fine now," he says and waits for the next question.

Ciara Glennon's story hangs heavily in the air-conditioned room. You want to ask this strong, silent Irishman how life has been over the last two years since his daughter went missing; to describe the torment they endured when her partially clothed body was found under some scrub by a passer-by three weeks later. How he and his family have coped when the man who police are 99.9 per cent sure perpetrated this atrocity is living a short drive away from their home.

"When it hits you first you are totally numb with shock. Then you go through a stage of absolute anger, a stage of questioning your faith, disbelief. You start to question the abilities of the police, and then there are periods, weeks and weeks without sleep, total exhaustion," he says.

Ciara was probably not thinking about it as she made her way along Stirling Highway in search of a taxi that night, but in the 18 months before two young women had disappeared from almost the exact same spot. Police had already highlighted the possibility of a serial killer after 18-year-old Sarah Ellen Spiers and, eight months later, 23-year-old Jane Louise Rimmer went missing. Like Ciara, both women were petite, young, attractive and well-dressed.

Sarah Ellen Spiers's body has never been found, but they found Jane Louise eight weeks after she went missing. It was 50 km south of Claremont, about four metres in from the road in dense vegetation. The Macro Taskforce was quickly established by Perth police, as it became clear that a serial killer was at large in the area.

The search for Ciara got under way immediately. By late Saturday afternoon the task force was making inquiries into her movements and by the end of the week they were imploring people to come forward with any useful information. Denise Glennon was married as planned that weekend - the bridesmaid's dress supposed to be worn by her best friend and sister left hanging in the wardrobe.

"It was a very difficult decision to go ahead with the wedding," says Denis Glennon. "But stripped of all the usual materialistic elements it was so much more meaningful and special."

Three weeks after she went missing, Ciara's body was found at a remote fishing location near Perth. The pain of this time has never left Denis Glennon's eyes but what also remains for him is the way a whole country, his business friends, the media, ordinary people took their awful family tragedy to their hearts.

Almost immediately afterwards the Secure Community Foundation was set up by Denis Glennon's colleagues to raise money for extra resources to help the police investigation. The funds paid for a DNA analyser to scan the oral swabs given by the hundreds interviewed after the murder. They paid for a retired FBI polygrapher (lie detector expert), Ron Homer, to travel to Western Australia for a month, allowing police to eliminate a large number of suspects and focus on the remaining group who had refused the test or who had failed it.

They also paid for an FBI psychological profiler to visit for a month to give police a better understanding as to the identity of the offender, his likely traits, his background, his lifestyle. The last time the funds donated by the SCF were tallied they came to A$850,000 (£390,000). It is the largest homicide investigation conducted in Australia.

In late October 1997 police in Perth identified the person they still suspect of being the Claremont serial killer. He was kept for 10 months under covert surveillance until April last year, 12 months after Ciara was found, when he was observed driving alone through Claremont's business district, stalking a girl who looked very like Ciara and the two other victims. He was interviewed at length that evening and has been under overt surveillance ever since.

A member of the Macro Taskforce said last week that the suspect, a 42-year-old civil servant, was driving home from work to his parents' house as we spoke. "He is a quiet, introverted, insignificant member of the community and the person we strongly believe is the Claremont serial killer," he said. The vital evidence they need for a conviction is proving elusive, however.

People tell you that Perth has grown up since Ciara Glennon's murder as women grow wary of going out alone, but inevitably as time goes by complacency is creeping in. The Glennon family has been dramatically altered, priorities shifted, perspectives changed.

"Previous to Ciara's murder I was no different than any other reasonably successful business man," says Denis Glennon, adding that "now life is much more about caring for our family. There has been a huge renewal in the meaning of faith amongst us."

The everyday ways in which the bitter grief has changed them are informative. Una Glennon used to watch "a reasonable amount of TV, partly crime-related stuff. Now she doesn't watch any," says Denis. Constantly travelling, he himself used to go through up to three novels a week. "Now I don't. It seems frivolous."

He does not view the apprehension of Ciara's killer in a vengeful way but "justice must prevail". "Finding the perpetrator will be like closing a chapter but it also means that the whole horror of what happened to Ciara will be revealed and I am not looking forward to that for any of our sakes," he says.

The Glennons realise that each of them must go through it in their own way. They haven't sought counselling and will not. Denis Glennon knows the statistics - that 80 per cent of marriages simply don't survive this kind of devastation - but his has come through the worst.

"You have to find the strength from somewhere," he says. "Everything is more meaningful now. We pray for Ciara all the time. When Una and I see a young woman of Ciara's age we think of her. Sometimes we choose to speak about it, sometimes we choose not to".

He chose to speak about it now for two reasons. He wanted to thank the Irish people for their support over the last two years. He also wanted to show how the tragedy has deepened the faith of the family, in the hope that it might have a positive impact on others. Faith helped them to choose between the way of hope and the way of madness. They chose hope.

"We really miss her but if we had a choice to bring her back from where she is now we wouldn't . . . we have to learn to live beyond it."