Mysterious woman with Mona Lisa smile

ourteen years after Keli Lane's daughter disappeared, many questions remain unanswered.

Keli Lane's secret life: Michael Duffy's Crime and Punishment blog

This was an extraordinary trial, not just because it involved the strongest bond there is, between mother and child. It was extraordinary because after more than four months, we know almost nothing more about Keli Lane's character, and her daughter's disappearance, than we did at the start.

The unusual thing about the case is that there was only ever one piece of physical evidence for the alleged murder. This was the fact that somewhere between lunch and dinner on September 14, 1996, 21-year-old Keli Lane was parted from her daughter Tegan. After what has been described as the biggest missing person search in Australian history, not one piece of physical evidence has been added to that: no scrap of clothing or DNA or fingerprint, no sighting of Keli or Tegan between the time they left Auburn Hospital and Keli arrived home alone. Nothing.

Of course, it was a circumstantial case, like those involving the deaths of Azaria Chamberlain and Caroline Byrne, and circumstantial cases by their nature are weak on direct evidence. This is even more so when the alleged victim's body is missing and there is not even a crime scene. Even so, usually there is more than there was here. Keli Lane's trial opened as a mystery wrapped around that one fact and it closed as one.

Still, the fact of Tegan's disappearance was so unusual and so terrible it had to be investigated. And once it had been investigated - several times, including a coronial inquest in 2005 - the Director of Public Prosecutions decided Keli Lane had to be prosecuted.

The facts of her life that have emerged were bizarre and they were many. They revealed a woman incapable of effective contraception, who in the 1990s became pregnant five times when she did not want children. A woman who was able to hide three pregnancies and births from those close to her, including her parents and a partner with whom she was having a regular sexual relationship and most of her water polo team mates. A woman who gave away at least two newborn children. Some of the details were so amazing they strained credulity, yet none added one jot of physical evidence to our knowledge of what happened on the afternoon of September 14, 1996.

Nor did Keli Lane's many lies about the children she had in the 1990s. These were told to hospital and adoption workers at the time, and to police and friends later on, when sharp-eyed DOCS worker John Borovnik realised Tegan had disappeared from the official radar and notified police. But telling lots of lies does not make you a murderer, as Justice Anthony Whealy warned the jury during the trial.

The mystery of Tegan's fate was reflected in the mystery of her mother. For more than 60 days Keli Lane turned up in court well-dressed and perfectly groomed, her unlined face composed in an expression of serenity. There were tears on only a few occasions. More often she displayed a faint smile that reminded this observer, disconcertingly but persistently, of the Mona Lisa. Sometimes she smiled at the judge, the jurors or some of the lawyers or witnesses. Compared with most people who have sat in the dock at King Street Court 3, she was a strong presence. Given the enormity of what she was charged with, and the bizarre and troubling nature of some of the evidence, her serene self-confidence was at times disconcerting.

Although we learnt a great deal about her life in the 1990s, the trial produced surprisingly little insight into her character. She refused to go into the witness box here, just as she refused at the inquest. What remains is a great disconnect between what we know she did - even putting aside the murder allegation - and the fact that by literally all public accounts she was a normal, happy and sociable northern beaches girl with a supportive and loving family, a passion for sport, and a healthy social life. There was no suggestion she had suffered postnatal depression or any mental illness. The vast gap between these two sides of her character was the second great black hole in the trial. Keli Lane was - she is - an enigma.

Senior Crown prosecutor Mark Tedeschi ran the prosecution. His recent successes include the murder prosecutions of Gordon Wood (who has appealed) and Des Campbell. In a circumstantial case the prosecution needs to disprove any reasonable alternative hypothesis that might explain the death of the victim. As in any case, the accused does not have to prove anything, but usually in circumstantial cases they do present an alternative explanation. Keli Lane had told hospital and welfare workers and police eight different versions of what had happened to Tegan, but the one she settled on during the police investigation was that she had given Tegan to the baby's father, Andrew Morris or Norris.

In theory this made the task of police and prosecution easier, as they knew the account they had to disprove.

Two other strands in the prosecution case were attempts to show Lane might have had a tendency to treat Tegan badly because of the way she treated other children she gave birth to around this time, and to show Lane had demonstrated consciousness of guilt by things she said later. A lot of the evidence on both matters involved what the Crown claimed were lies, and by the end this became a trial about lies and their importance.

The idea of lies was built into the indictment. Keli Lane was charged not just with murder but with three counts of perjury, in relation to things she had told hospital and adoption staff about her other babies. This enabled Tedeschi to present a great deal of information not directly relevant to Tegan's disappearance but which the jury might decide was relevant to the way Lane felt about having children at that time in her life, and also about her truthfulness.

Tedeschi opened the trial on August 9 with a riveting 6½ hour speech that wove all the elements of the circumstantial case - many of them speculative - together. It was a masterly performance, as gripping as listening to a first-rate crime novel.

Most of the subsequent evidence involved two aspects: the alleged lies relating to the births of Tegan and the siblings on either side of her, and the many police searches for Tegan and Andrew Morris or Norris. Just one of these involved seeking details from 9491 primary schools around Australia. The jurors were given coloured flow charts to help them comprehend what had been done, and by the end of the trial each had several fat ringbinders of documents provided by the Crown and the defence barrister, Keith Chapple, SC.

Justice Whealy, while prepared to allow an enormous amount of detail into evidence, was sceptical about the prosecution's attempts to attribute meaning to much of it. For example, in 2004 police intercepted telephone conversations between Keli Lane and her friend Kati Cummins, who seemed to be having trouble understanding why Lane was so concerned by the questions being asked by a detective.

"But he's got nothing," Cummins said, "so how can something come out if he's got nothing?"

Lane replied, "Because that's, he wants to, he wants to find out what he doesn't have."

Later in the conversation Kati said, "The worst thing that can happen is, the hardest thing you'll ever do is telling [people about giving Tegan away]. And once you've told them, it'll be all right."

To which Keli responded, "But, it's going to keep going on, that's the thing. If I knew that by telling them, that would end it, that would be great, but it's not."

Tedeschi wanted to argue this was evidence of consciousness of guilt, but Justice Whealy refused. He said it might just mean Lane suspected it would be a long investigation.

For those who became immersed in the detail of the case, after a while it was possible to forget the raw fact of Tegan's disappearance and the strangeness of her mother's refusal to give evidence. The length and complexity of the trial threatened to shift the focus onto the many tedious details of the police search for Andrew Morris/Norris and for Tegan.

This was an area of diminishing returns for everyone involved, because it was never going to be possible for the Crown to establish with 100 per cent certainty these people do not exist. It is just incredibly unlikely. Arguably, that was as clear when the trial began - it was as clear five years ago - as it is today.

It would be fascinating to know how this jury reached their decision. Maybe it was because of the overwhelming detail of the police search, and the meticulous nature of the Crown case. Or maybe it was because of a far simpler consideration, the belief that a mother should not be allowed to lose her baby between lunch and dinner and be unable to account for that.