Did `Aunt Flo' walk to her own death? Her 67-year-old niece, convicted of murder, is due for a retrial.
Three and a half years ago Sheila Bowler was led from the dock to begin a life sentence for murder, and an education in the drugs and violence of prison life that her comfortable, middle-class world had not prepared her for.

Mrs Bowler, 67, still cannot believe that anyone could think her guilty of killing her late husband's elderly aunt. And she is convinced she will not survive until 2005, her earliest potential release date.

"I have to get out," she says. "I will die if I have to stay in here. I could never take my own life but I will shrivel up and die, or my mind will become distorted. I will not survive another eight and a half years in here."

The daughter of a solicitor, brought up as a strict Methodist, Sheila Bowler was a recently widowed, well-respected music teacher in Rye, East Sussex, when she was arrested in May 1992 and accused of pushing 89-year- old Florence Jackson into the river Brede.

In a mystery worthy of Agatha Christie, the wear and tear on a pair of slippers, an unprepared bed and a missing walking-stick and torch became sinister clues in the absence of any evidence as to how "Aunt Flo" came to be in the river.

It was about 8pm on 13 May 1992 when Mrs Bowler collected Aunt Flo from Greyfriars Residential Home in Winchelsea to take her home for the weekend. Driving down a hill, Mrs Bowler said she felt her steering fail. She stopped the car and found she had a partially flat tyre. As she had no spare wheel, she decided to call for a recovery service from a nearby house. When she returned to the car about 30 minutes later with the people from the house, Aunt Flo was nowhere to be seen. Mrs Bowler's immediate thought was that she could not have walked far. Thirteen hours later a police helicopter spotted Aunt Flo's body lying in the water, 650 yards away from the car.

The police appear to have fastened on to Mrs Bowler as a suspect fairly early on. Her abrasive manner and refusal to give way to emotion - which friends say hide a heart of gold - clearly antagonised those searching for answers.

A look at Aunt Flo's will provided a motive - to stop the pounds 252 weekly cost of keeping her in a residential home haemorrhaging away the value of Aunt Flo's flat, which Mrs Bowler was due to inherit. But proving their case - that Mrs Bowler had driven her aunt to a pumping station beside the river Brede, where she pushed her into the water before driving back to the road and deflating her tyre - was more problematic.

There was no forensic evidence to link Mrs Bowler with the river bank or with the injuries her aunt had sustained. There were no tyre marks or footprints, and no blood or mud was found on Mrs Bowler's clothes. However, officers returning to Mrs Bowler's home found that there was no bed made up for Aunt Flo - either because she knew her aunt would not be coming back or because, as Mrs Bowler says testily, she did not know whether her aunt would manage to get up the stairs or would need a bed downstairs.

The walking-stick and torch that Mrs Bowler said were missing from the car were never found - because they were washed away by the river, or because they never existed?

The police did consider the possibility that Aunt Flo's death was an accident - they sent someone shuffling down the road in similar slippers to see whether anything could be proved from the wear and tear on the real slipper found on the riverbank - but they discovered nothing conclusive.

However, at Mrs Bowler's trial in July 1993, her defence team did not seek to argue that Aunt Flo's death was accidental. Instead, they set about demolishing the prosecution case with great effect, arguing midway through the trial that there was no case to answer. In the absence of the jury, the trial judge, Mr Justice Garland, agreed that every plank of direct evidence against Mrs Bowler had collapsed. But, in a crucial decision, he ruled that the jury was still entitled to ask: "If not the defendant, then who?"

Since there was no evidence of anyone else's involvement, and since it was widely accepted that Aunt Flo could not have made the fatal journey by herself, the jury came to the understandable conclusion that Mrs Bowler must have been guilty.

After the trial, her friends and family, including her son Simon, 30, and daughter Jane, 27, were desperate. They dismissed the so-called motive for murder as senseless. At the trial, Aunt Flo's flat in Rye had been said to be worth pounds 30,000. But it was dark and dingy, and sold recently at auction for only pounds 18,000.

Mrs Bowler, on the other hand, was comfortably off. The mortgage on her pounds 150,000 family home had been paid off 12 years earlier. She had an income of about pounds 17,000 a year, including a teaching salary and pension, and she had about pounds 15,000 in investments.

The one glimmer of hope is that her case, which is now being considered by the Home Office minister Timothy Kirkhope, will be referred back to the Court of Appeal, even if it means facing a retrial. Her case could be one of the last to be decided before responsibility for investigating alleged miscarriages is handed over to the new Criminal Cases Review Commission on 31 March.

For the former journalist Tim Devlin, who is leading the campaign for Mrs Bowler's case to be reconsidered, the clinching reason for his belief in her innocence was the timing of Aunt Flo's death. "Sheila cared passionately about her daughter Jane's musical career," he says. "It is inconceivable that she would have committed such a cruel and callous murder on the eve of Jane's final music degree examination."

But gut feelings are not enough to persuade the Court of Appeal to overrule a verdict: there must be fresh evidence, or the trial judge must have erred in law when summing up the case.

The Channel 4 series Trial and Error became interested in Mrs Bowler's case and ran the first of two programmes on it in September 1994. It came up with what seemed the obvious answer - that Aunt Flo, like many occupants of old people's homes, was much more mobile than had been imagined. She was also on diuretics and was terrified of being left alone - cause enough to make her struggle out of the car and shuffle along the road to her death.

But, in May 1995, the Court of Appeal decided that the expert geriatrics evidence put before them was theoretical and they preferred the evidence of the people looking after her - and of Mrs Bowler herself - that Aunt Flo could not have walked any distance on her own.

However, her barrister David Martin-Sperry said there was no evidence that her carers were medically qualified, while Mrs Bowler's insistence that her aunt could not have walked far should have been considered from a psychological viewpoint and not taken as her instructions on the issue: "When she said, on finding out her aunt was dead, `she couldn't have walked', it was wishful thinking. Mrs Bowler did not want her to have walked, which would have meant living with the responsibility of not having looked after her properly. Furthermore, by saying that, she was cutting off her sole line of escape. That is not the behaviour of a guilty defendant."

Meanwhile, Mrs Bowler's legal team has been working on new lines of medical evidence to support the theory that Aunt Flo's death was an accident, as well as gathering more expert geriatrics evidence backed by case histories highlighting the often surprising mobility of elderly people.

For Mrs Bowler, focusing on the problems of her fellow inmates in Holloway is her way of keeping a grip on her own fears. Her health has suffered. She had a slight stroke last year while being held in Bullwood Hall in Essex. "If I get out, there may be people who will still believe I was responsible for her death and will shun me, but I will just ignore them," she says. "Jane said I should not go back to Rye, with all the gossip, but it is still my home."