Paul Williams: Scattering of remains had all the hallmarks of a panicked killer
Even in a society that has become almost desensitised to barbarous acts of violence, the gruesome discovery of dismembered human remains is truly shocking.
It speaks of a crime that is the result of atavistic, primitive behaviour that chills all humans to the core - with the exception of textbook psychopaths.
When a human torso was first discovered off the Military Road last weekend, it was at first thought to be that of a young man in his mid-20s.
And the first, and most logical, assumption was that this was yet another act of savagery committed by a criminal gang.
As other body parts began to be discovered over a large area, it became clear that the killer, or killers, had dumped the remains while driving across the mountains.
The Dublin and Wicklow Mountains have been the scene of many gruesome discoveries throughout the decades as individual killers used the wilderness on the capital's doorstep as a dumping ground.
It was just off the Military Road in Rathfarnham that the skeletal remains of a missing woman called Elaine O'Hara were discovered in September 2013, which ultimately led to one of the most harrowing murder cases in our history. But this particular investigation was different, as indeed are the circumstances of all murder cases.
From the first discovery of a human torso, it was clear that this was a classic example of a crime that was both disorganised and unplanned.
The common scenario found in similar cases that have been the subject of international criminological study is that the victim is known to their attacker, was unintentionally killed in a moment of violence, and that the killer then panicked.
In the ensuing chaos, the panicked assailant desperately tries to cover up the crime by disposing of the body, even resorting to acts such as dismemberment which might, in difference circumstances, be considered repulsive and unimaginable. That appears to be what happened in this instance.
The victim has been identified as grandmother Patricia O'Connor, from Rathfarnham in south Dublin, who was reported missing on June 2.
It is understood that the killer hit her over the head with a blunt object, claiming it was a momentary act of madness.
He then panicked, put his victim's body in the boot of his car and later drove to Kilmuckridge, Co Wexford, where he dug a shallow grave and attempted to bury the body.
But still in a panic, at some stage he changed his mind and returned it to the car. Later he cut up his victim's body with a hacksaw and made the journey back to Dublin across the Wicklow Mountains.
As he did so, he disposed of the body parts across an area of at least 30km.
When initial reports emerged in the media over the weekend that a human torso had been found, it appears the killer again began to panic.
On Monday, a man walked into a Garda station and made admissions. At that stage, the gardaí believed that the remains were those of a male in his mid-20s and therefore that the man was a fantasist.
But as the searches for body parts continued, officers travelled to the grave that had been dug in Wexford. When the detectives saw human hair, teeth and blood they realised that they had made a breakthrough.
The man was arrested and brought in for questioning. He sits in a police cell awaiting a trip to court.