Jean Jones, 50, said Sue Woodward, Louise's mother, "rode roughshod" over those trying to help and became obsessed with the money being raised.
Her harsh words strike at the reputation of the Woodwards at a crucial point in the saga: Louise Woodward, now 20, is waiting for the results of an appeal against her manslaughter conviction which could come any day.
Ms Jones' comments came after a week of bitter recriminations over the appeal fund, sparked by Elaine Whitfield Sharp, the lawyer who helped to defend Louise Woodward after baby Matthew Eappen died in her care. Ms Whitfield Sharp claimed the Woodwards had forged claims they made on the fund.
She said Mrs Woodward had falsified a pounds 9,000 invoice for accommodation even though Ms Whitfield Sharp had looked after Louise in her home without payment.
The trustees held an emergency meeting and announced their continuing faith in Susan and Gary Woodward, who live in Elton, Cheshire. But their support failed to end the dispute because Daniel Sharp, the lawyer's husband, accused the trustees of not answering the claims.
While most people in Elton refused to criticise the Woodwards yesterday, Ms Jones said "the money became God" for Sue Woodward.
"She rode roughshod over everybody. She was the most ungracious person I have ever met in my life," she told Sky News.
"She didn't have any thought for other people. I didn't care about myself because I decided to come out. But being outside looking in, I've seen how these people work, the kindness coming from their hearts, working for this family and she didn't give a damn about those people."
Ms Jones said the fund should be now stopped. "God bless all the people that helped and worked so hard - it's time to go home and go back to your own lives."
The Rev Ken Davey, Elton's vicar and chairman of the fund, said that Ms Jones had lost sight of what the fight was about. "I think it is a shame that this division is creeping in," he added.
"But I hope, in fact I am certain, that the vast majority of the villagers are still with Sue Woodward."
Sandra McCabe, who also helped found the fund, called Ms Jones a prima donna. "Sue Woodward can prove she has got Louise's interests at heart. There was no need for Sue to do what Elaine Whitfield Sharp says she has done."
However, the stress was getting to everyone, Mrs McCabe added. "I wish the courts would make a decision soon."
The Supreme Judicial Court in Massachusetts is expected to make its ruling any day. It can quash the conviction, allow it to stand, or reimpose the original life sentence for second- degree murder which was overturned by Judge Hiller Zobel last year. The defence has filed a fresh claim because of evidence the medical officer in charge of the post-mortem examination on Matthew failed to perform a key test in another trial.Reuse content