Theresa Riggi, who killed her three children, is now being held in “top secret” outwith Scotland, a court was told today.
Riggi, 49, originally from California, is serving 16 years for the crime, which shocked the country in 2010.
She stabbed each of her children - eight-year-old twins Austin and Gianluca, and their sister Cecilia, five.
She then allegedly tried to cover up their deaths with a gas explosion, before trying to kill herself by leaping out of their second-floor Edinburgh flat.
She was originally charged with murder but later admitted culpable homicide on the grounds of diminished responsibility.
She was held in Cornton Vale Prison, Stirling, before being transferred to secure psychiatric care.
It it is alleged that in November 2011 in Cornton Vale she was disfigured for life by another woman who was an inmate at the time, Angela Hamilton, who is accused of slashing her with a razor blade.
At Stirling Sheriff Court today Hamilton, 40, whose address was given on court papers as Leverndale Hospital, Glasgow, maintained her plea of not guilty to the offence.
She faces a single charge which alleges she repeatedly struck Riggi’s face and head with the blade, during the alleged attack in the killer’s cell at Cornton Vale.
She faces trial by jury in March.
Solicitor Murray Aitken, defending, said the prosecution had applied for Riggi to be excused from giving evidence, on the grounds of her mental state.
The Crown has lodged an application for Riggi’s evidence at the trial to be read in the form of a sworn statement.
Mr Aitken said the defence challenged whether Riggi’s mental state justified the procedure, which, he added, could be unfair to Hamilton.
He said Hamilton’s defence team was hoping to interview Riggi’s doctor next week about the killer’s condition.
At one stage, Riggi was being held in a secure hospital unit in Edinburgh, but it is now understood she is being held somewhere in England.
Mr Aitken told the court: “She is furth of this jurisdiction in a top secret location, and that is causing some difficulties as well.”
He asked the court to set a date for a “proof” hearing at which Riggi’s doctor can be questioned on Riggi’s fitness to give evidence.
Mr Aitken said the defence wanted to challenge the Crown application to keep Riggi out of the witness box on two possible grounds.
He said: “It will be challenged on a factual basis, and there may also be a fairness issue, given that this witness is the only witness to the events.”
Sheriff William Gilchrist set March 13th as the date for the “proof” hearing, with a preliminary hearing on March 6.
The case, transferred from Falkirk, where proceedings started, is presently set down for trial in a sheriff-and-jury sitting at Stirling commencing on March 20.
Before the killings, Riggi had moved to Edinburgh with her children from Aberdeenshire following the break-up of her marriage to their father, Pasquale Riggi.
The High Court heard that Riggi had been a protective mother who was involved in a custody battle with her estranged husband over access to the children.
High Court judge Lord Bracadale described the killings as “truly disturbing” and “grotesque”,