GARDAI investigating the recent murder of two women in Grangegorman, Dublin, have called in British experts in drafting logical profiles of serial killers.
No suspect has emerged yet in the search for the person who stabbed both women to death, then mutilated their bodies, inflicting wounds of an extent and nature never previously encountered in a murder investigation here.
In one case there was extensive genital mutilation. Gardai acknowledge that they have never encountered such behaviour in a murder and that they have no clear idea of the type of person they are seeking.
The victims, Mary Callinan (61) and Sylvia Shields (57), had been patients attached to St Brendan's Psychiatric Hospital and lived in sheltered accommodation. Both were killed in their first floor bedrooms more than two weeks ago.
A third woman, who slept in a ground floor bedroom in the same house, was untouched and raised the alarm after finding the bodies the next morning.
The killer seems to have gone to the house prepared for murder and mutilation. No fingerprints have been found and it is believed the killer wore gloves and may have brought a change of clothes.
A series of incidents and potential suspects are being checked as part of the major investigation run by the National Investigation Bureau and detectives in north central Dublin.
On the night of the killings a taxi was hijacked in unusual circumstances by a man who had been riding a bicycle on Baggot Street. He for the driver out of the car in Merrion Squad and the car has not been found.
The same evening a man in a car, thought to be a black Volkswagen Polo, attempted to force a prostitute into a vehicle in Benburb Street not far from Grangegorman. But senior gardai say there is nothing to connect these incidents with the murders.
The two psychological "profilers" from Scotland Yard have been brought in to provide gardai with some indication of the type of person they are searching for and to estimate the likelihood that the murderer will kill again.
Dr Art O'Connor, consultant forensic psychiatrist at the Central Mental Hospital, said the killing of two people at once was a rare enough occurrence and referred to the case of Brendan O'Donnell, who abducted a mother, her child and a priest and killed them in east Clare in May 1993.
"People who decide to be serial killers go through a period of months or years of fantasising and doing nothing and then can progress and stalk people or break into houses and upset furniture instead of injuring someone. They may commit a sexual offence, but this is a prelude to the ultimate commission.
"It is likely there was a lead in period of months or longer where there was fantasising and it reached a crescendo. The person would be shocked, amazed and thrilled [by what he/she did] and sometimes is relieved. He can say he will do it again or sometimes is so shocked by his actions that he gives himself up," Dr O'Connor said.
He said that cases involving murder and child and wife abuse were getting more and more disturbing. "You end up with one case and say to yourself we have now reached the maximum and then a number of months later something else happens which is even more outrageous."