She portrayed Guerin, who lived on a farm with her new husband Richard, as wealthy.
But judges described Guerin as a dutiful and loving daughter in court documents, who had cared for her mother for most of her elderly life. The mother and daughter had bought a house and lived together in Gisborne for several years before Guerin met her husband.
In 2005, Hayes, a gifted academic who uses several aliases, turned up on her mother's doorstep wanting to move in.
Guerin says she became concerned after coming to the house to find no food in the kitchen and the heating turned off in the middle of winter.
"Judith says she was concerned about what she saw as Marta's inadequate care and financial exploitation of Elizabeth," court documents say.
Guerin, a semi-retired science teacher, says she was desperate for Elizabeth to come back to live with her. Instead, she received a "bombshell": she had been written out of the will entirely.
A few months later Elizabeth suffered a stroke, which left her severely disabled and unable to speak. She prepared another will, naming Guerin as sole executrix and dividing the estate evenly between the two sisters.
Elizabeth stayed with Judith and her husband Richard on their farm just outside Gisborne for 18 months until she died in January 2007, aged 92.
After the death both women filed court action.
A High Court judge upheld the second of the three wills, but ordered Hayes to pay $80,000 to Guerin. Hayes appealed against the decision, first to the Court of Appeal. This month, The Supreme Court dismissed her application for leave to appeal.
Hayes is said to live a transient life, though a judge indicated she might own several properties she had not declared.
The sisters were raised together in California but were never close, says Guerin.
"She was very reclusive. Mum often encouraged me to take her water skiing but it was difficult to include her."
Guerin, a mother of two, moved to New Zealand in 1972. Her mother followed in 1980.
Court documents show Hayes came to New Zealand after fleeing Texas with her son in 1992 to evade a parenting order. Hayes, who has a PhD from Canterbury University under the name Laura Kolonie, could not be reached for comment this week.
Guerin said the case had eaten up much of her retirement savings, her energy and caused an irreparable rift between her and her half-sister.
"The whole thing has been a colossal waste of taxpayer money and to what end?"
