Mrs Bowler, 68, who had always protested her innocence, was convicted at Hove Crown Court in 1993 of murdering Florence Jackson. But the Court of Appeal quashed the conviction and ordered a re-trial last year after new medical evidence emerged.
Mrs Bowler, from Rye, denied murdering Mrs Jackson in May 1992 while driving her from a residential home to her own house. The prosecution alleged that she had dragged Mrs Jackson from her car to the river. Her body was found the following day.
Anthony Glass QC, for the prosecution, alleged that Mrs Bowler killed Mrs Jackson on the journey then covered up her deed by pretending her aunt - who normally needed help to walk - must have made her way to the river and accidentally fallen in. Mrs Bowler said she had left Mrs Jackson - known as Aunt Flo - in her car when she went to get help for a flat tyre. When she returned she had disappeared.
Jeremy Roberts QC, for the defence, said the prosecution "had not produced one shred of direct evidence to connect Mrs Bowler with whatever it was that happened to Mrs. Jackson that night". He told the jury: "No witness claims to have seen Mrs Bowler or her car at the pumping station or in Station Road that night. There is no scientific evidence suggesting Mrs Bowler had ever been in that area."
Professor Archibald Young, an expert in geriatric behaviour, who was called as a defence witness, had told the jury that people of Mrs Jackson's age and condition could have walked the quarter-of-a-mile from the car to the river by themselves.
The court had heard that Mrs Jackson was the aunt of Mrs Bowler's late husband, and that her only asset was a flat in Rye which she was leaving to her niece. Mrs Bowler had power of attorney and was responsible for arranging payment of fees at Greyfriars, a residential nursing home at Winchelsea where Mrs Jackson lived. She owed more than pounds 3,000 in arrears and the flat would have to be sold.
Mr Glass alleged that she had a financial interest in Mrs Jackson's death, saying that every month Mrs Jackson lived, the value of Mrs Bowler's inheritance diminished. But Mrs Bowler said that she received pounds 17,500 a year from teaching at private schools and pensions. The mortgage on her home was paid off and she had savings.
After the verdict Mrs Bowler said she felt vindicated. "I do not feel bitter, but I am very angry that I had been convicted [earlier] of this. I lost my faith in the justice system," she said, adding that her ordeal had been "a living nightmare".
The campaign to free her was led by Tim and Angela Devlin, whose daughters were contemporaries of Jane Bowler at school. Tim Devlin's father, Lord Devlin, played a part in the release of the Guildford Four.
Channel Four said yesterday that a special edition of Trial and Error, which investigated the Bowler case, will be broadcast on Monday, showing Mrs Bowler, her family and lawyers, as they prepared for - and during - the 17-day retrial.
Prison diary, page 15