Kathleen Folbigg was convicted in 2003 of murdering her four children.

Lindy Chamberlain spent three decades mired in Australia’s most notorious child murder case before she was completely exonerated of her daughter Azaria’s death.

And last week Helen Cummings, first wife of a man who went on to kill his second family and himself, warned NSW Attorney-General Greg Smith about the danger of history repeating itself in an emotional appeal to free Folbigg from jail.

The case against Folbigg had ‘‘all the hallmarks of another Lindy Chamberlain’’, wrote Ms Cummings, the daughter of former Newcastle lord mayor Joy Cummings.

‘‘I have been corresponding and visiting Kathleen Folbigg now for over a year and I have no doubt at all about her innocence.’’

Ms Cummings told Mr Smith that if there was anything he could do to prevent a long, painful and protracted campaign, she would be grateful ‘‘until the end of my days’’.

Ms Cummings is leading a campaign to have Folbigg’s case reviewed after a 2011 book by an Australian academic lawyer, Murder, Medicine and Motherhood, concluded Folbigg was wrongly convicted.

The legal process decided Folbigg was a ‘‘monstrously guilty mother’’ despite the failure of medical experts to say how her four babies died, academic lawyer Emma Cunliffe found.

‘‘The groundwork of an appeal for a review of the case has already been done in Emma’s book,’’ Ms Cummings said.

‘‘I contacted Emma because I always had an uncomfortable feeling during Kathleen’s trial that it was actually her mothering that was on trial.

‘‘She was totally hated and despised by society, and locked away.

‘‘We saw that with Lindy Chamberlain, and the same thing has happened to poor Kathleen.’’

Ms Cummings sent a copy of her book Blood Vows, about her first husband’s murder of his second wife and young daughter, and suicide, to Folbigg in early 2012 ‘‘to let her know where I was coming from’’.

Their first meeting in Silverwater jail started with ‘‘a hug for a long time’’. Two former childhood friends of Folbigg, Alana House and Tracy Chapman, are also regular visitors, supporting the campaign for a review.

In letters and monthly meetings between Ms Cummings and Folbigg since then, ‘‘nothing has been off limits’’.

‘‘She’ll talk about her children, what ages they are now. At the time it happened she was just so devastated, so beaten down. She’d not only lost them but she was blamed for their deaths.’’

Ms Cummings said Folbigg had no animosity towards her former husband and the babies’ father, Craig Folbigg.

Mr Folbigg was initially supportive of his wife after the death of their fourth child, Laura, in 1999, but after seeing disturbing excerpts from his wife’s diaries Mr Folbigg’s support ended.

The diary excerpts included one written in 1998, when Laura was five months old, in which Folbigg wrote she was ‘‘scared [Laura] will leave me now. Like Sarah [her second child] did. I knew I was short-tempered and cruel sometimes to her and she left. With a bit of help.’’

Attempts to contact Mr Folbigg yesterday were unsuccessful.

In a response to Ms Cummings’ letter to Mr Smith last week, a Department of Attorney-General and Justice spokesman said Folbigg had several avenues of review available to her, although they were ‘‘only possible in exceptional circumstances’’.

The Supreme Court could order an inquiry or refer the matter to the Court of Criminal Appeal.

The NSW Governor could also be petitioned, and refer the matter to the attorney-general for consideration of an appeal or direction from the Court of Criminal Appeal.

Supporters of a review include one of Australia’s leading forensic science legal experts, Gary Edmond, who said Folbigg’s case was tainted by unreliable, misleading and outdated medical evidence.

Ms Cummings said she was ‘‘feeling quite confident that Kathleen will be released before the end of 2013.’’

‘‘The ball’s rolling now,’’ she said.