The justice minister has asked to be briefed on why the Public Prosecution Service dropped a case against a woman who admitted ill treating a pensioner.
It happened on the day Patricia Young, 54, of Mandeville Avenue in Lisburn was due to be sentenced.
David Ford has asked his officials to find out what happened in the case.
A human rights group has also raised concerns. It said the incident undermined confidence in the justice system.
Ms Young pleaded guilty last month to ill treating Ivy McCluskey.
Hidden camera footage taken by the McCluskey family is said to show Patricia Young eating the food that was prepared for the pensioner in her care.
Mrs McCluskey, 70, could not speak, had Alzheimer's disease and was suffering the effects of a stroke. She has since died.
Her family attended hearings at Lisburn Court every day during the past six months and turned up on Tuesday expecting Ms Young to be sentenced.
Instead, they were told the whole process has to start again from the beginning.
Afterwards, they were too upset to talk about what happened, but they nominated someone to speak on their behalf.
She said: "The case is now null and void - actually today is the first day of the case all over again and I have absolutely no idea where this leaves the family or who is responsible for making a mistake like this."
Mr Ford also wants answers.
In a statement, the Department of Justice said the minister has asked his officials to provide him with a full factual briefing. It is understood those officials will speak to the Public Prosecution Service.
A spokesperson for the Public Prosecution Service would only say that the defence had raised a legal issue relating to the validity of the proceedings.
A human rights group that monitors the criminal justice system said that was not good enough.
Aideen Gilmore, deputy director of the Committee on the Administration of Justice (CAJ) said: "What is particularly striking is the lack of information from the prosecution service and what seems to be a lack of communication with the families and the victims and the accused, which raises questions about the accountability of the prosecution service where mistakes have been made."
Another case against Ms Young has now begun - on the same charges. The case has been adjourned for three weeks.
The BBC has learned that the PPS lodged the papers for that new case almost three weeks ago, but Ivy McCluskey's family were only informed about the move until Tuesday.
This comes just weeks after another embarrassing blunder by the PPS in a case at Enniskillen Magistrates Court.
Charges against three men accused of assaulting police at a republican parade in County Fermanagh were dismissed because a prosecution lawyer failed to turn up to argue the case.