THE curious chain of coincidences that began on Wednesday last week in the Wicklow Mountains and ended in woodland 20km away on the edge of Dublin has uncovered a killer who probably thought he would never be caught.
The caretaker of Vartry Reservoir near Roundwood was inspecting the water level, which had fallen several feet as a consequence of a rare hot summer.
In the shallow water, he spotted a number of items which, on closer examination, turned out to be ankle cuffs and handcuffs. He handed them in at the local garda station.
The strange objects could easily have been placed on a lost and found shelf to be dealt with another day or forgotten, but the conscientious garda logged the find on to the Pulse system.
By doing so, he had just made a major breakthrough in a murder that was still to be detected.
On Friday evening of last week, three days after the caretaker set out to inspect the reservoir, a woman walking her dog in Killakee Woods in the foothills of the Dublin Mountains made a grisly discovery.
The dog had disappeared into undergrowth in dense forestry 200 metres from the road and refused to return.
When the owner went to investigate, she saw skeletal remains under the thick bushes where they had lain undetected, we now know, since August 24 last year when Elaine O'Hara was last seen.
On Saturday morning, gardai from Rathfarnham began a search of the area and discovered part of a fibula, tibia, jaw bone and pelvis. They also found the ragged remains of some clothes and a pair of size seven runners.
Of particular interest were size 16 tracksuit bottoms, which gave a clue as to the victim's size – Elaine O'Hara was described as a heavy set woman.
The deputy state pathologist and a forensic anthropologist visited the scene and carried out an examination.
They determined that the remains were those of a woman aged between 25 and 40 and, from the state of decomposition, the body had been there no more than a few years.
This immediately ruled out the cases of women thought to have been abducted and murdered in the 1990s.
Meanwhile, detectives based in Dundrum, who had investigated Ms O'Hara's disappearance in 2012, believed the description coming from Killakee Wood could match their missing person.
On Tuesday morning, an officer spotted the Pulse report of the bondage items found at Roundwood. It is understood that during the initial missing person inquiry, gardai discovered that Ms O'Hara had been visiting specific websites.
The detective alerted the garda in Roundwood and he went to search the spot where the items were found.
There he saw car keys lying in the water and, when he fished them out, he noticed a Dunnes Stores loyalty card attached.
A check confirmed that the card belonged to Ms O'Hara. It had not been used in more than a year.
In another coincidence, gardai in Dundrum made the breakthrough around the same time that forensic experts confirmed the victim's identity through her dental records.
The officer now in charge of the murder hunt, Chief Supt Diarmuid O'Sullivan, ordered divers to search the reservoir.
The shallow waters gave up more important clues. A bag and other restraint objects including handcuffs were found.
But crucially, a mobile phone was also located.
Gardai believe the items were dumped at the same time that the murder took place.
Since the discovery, the investigation into Ms O'Hara's murder has gathered momentum and gardai appear confident they will solve it.
In Killakee, officers have continued to find skeletal remains as their search spreads out over a 30m radius.
They are trying to establish if the victim was murdered at the spot where her body was found or elsewhere.
The discovery of the phone, believed to have been a second one used by Ms O'Hara, is the biggest development.
Despite having been in the water so long, experts can trace calls and text messages made to and from it through its IMEI code and sim card.
Officers are also involved in an international trawl of traffic on a number of specific websites in their hunt for the killer.
The man responsible for Ms O'Hara's horrific murder has left no detectable DNA evidence to link him with the crime.
But ironically, his victim has left an electronic trail that is leading gardai to his door.