Gardai searched behind electrical fittings and wall cavities in convicted killer Graham Dwyer's home for an electronic memory card they believe contained horrific material, a new book on the murder of Elaine O'Hara reveals.
Working in consultation with a trained Garda psychologist, detectives believe the memory card still exists and say they will continue in their efforts to find it.
The book reveals the assumption is based on an analysis of a sordid story entitled 'Killing Darci' which was found along with other disturbing material that proved Dwyer's fascination with knives, blood, rape and murder.
The shocking material had been deleted but was recovered by Garda computer experts on a hard drive seized during a search of Dwyer's Foxrock home.
Videos of the 42-year-old married father of three stabbing women, including his victim, while having sex were also recovered on storage devices.
But Gardai later searched behind electrical fittings and wall cavities in the architect's home for a memory card.
The revelations are contained in an explosive new book on Ireland's most notorious murder by veteran crime writer Paul Williams, which is being serialised today in the Irish Independent and tomorrow in the 'Sunday Independent'.
'Almost The Perfect Murder' tells the complete inside story of the disturbing case which shocked the nation, and the extraordinary Garda investigation which unmasked Dwyer and brought him to justice.
Williams also reveals the belief among detectives that Dwyer filmed the childcare assistant's murder when he lured her to Killakee Woods, in the Dublin Mountains, on August 22, 2012.
The writer interviewed several former close friends and colleagues of Dwyer, who hid his secret predilections from his wife and family. They revealed a number of behavioural quirks and incidents that, with the benefit of hindsight, were signs of his darker side.
Dwyer was convicted following a three-month trial, which was one of the most shocking to come before the courts in Irish criminal justice history.
The book also details the Garda investigation and how it demonstrated Dwyer's ability to manipulate vulnerable women whom he met online.
One of them, young US woman Darci Day, would prove critical as a witness for the prosecution, as Dwyer knew only too well.
And it sets out how a Christmas card Dwyer sent to Day, on foot of a statement she provided, proved to be vital to her providing evidence.
Dwyer had discussed Elaine O'Hara's suicidal ideation with Day and he knew her evidence would clearly be of huge benefit to the prosecution as it could confirm his connection with the victim and his intention to kill her. And she could also corroborate his predilection for rape and murder.
"On December 22, 2014, Darci Day contacted Detective Ryan Brockway from the Major Crimes Unit of the Maine State Police, who had been liaising with her on behalf of the guards. She was in panic and seemed terrified. That morning, out of the blue, she had received a Christmas card from Graham Dwyer. The message inside was short and to the point.
"Dwyer told her that he was being wrongly blamed for a murder that had really been a suicide. He said there was no forensic evidence linking him to the death and that there was no evidence to suggest that Elaine O'Hara had been murdered. The lack of evidence meant that he was confident of an acquittal - and freedom. Dwyer wanted Darci Day to know that he knew where she lived if he ever fancied a visit once he had regained his freedom. He signed off by wishing her and her dog, Bruno, a merry Christmas.
"The card subtly conveyed the message that Day's evidence would make no difference to the outcome of the trial, which was a foregone conclusion, and it was obvious that he knew where she lived and could come and visit her," the book says.
Dwyer's ploy proved a miscalculation and was viewed as an attempt to intimidate a witness.
Almost the Perfect Murder will be serialised this Saturday and Sunday in the Irish Independent and Sunday Independent. Independent.ie readers can now pre-order a signed copy of the book with free delivery for €19.99.