Can the face technology that helped to unmask McDaid... also unmask British jihadist filmed beheading journalist James Foley?
A suspected British jihadist filmed beheading a journalist could be unmasked using cutting-edge facial-mapping technology successfully used by investigators in Northern Ireland.
Video footage of James Foley, an American reporter, being decapitated met with widespread revulsion after it was posted online by Islamic terrorists.
The masked killer who carried out the brutal act appeared to speak with a British accent – sparking a huge intelligence operation to identify and bring him to justice.
One of the techniques being used by the FBI and British intelligence to track the world's most wanted man has been used to identify paramilitaries here. Last year it led to two convictions, with 150 paramilitary-style attacks currently being re-investigated with the aid of the technology.
The former MI6 director of global counter-terrorism, Richard Barrett, said he was convinced the killer of Mr Foley – referred to as 'John' – would be brought to justice.
"They will be able to identify him, although there are four or five hundred people who have gone from all over the United Kingdom. Many of them have made their presence there known and I think the community will be able to recognise this person and I am sure many in the community will be keen to do so," he said.
"I mean the intelligence community certainly, but also the community from which this man comes. He will have had many acquaintances and friends in the United Kingdom and those people will wish to see him brought to justice."
The PSNI said facial-mapping technology could lead to dozens of those responsible for previous paramilitary-style shootings and assaults throughout Northern Ireland being brought to justice.
Specialists within the force are currently examining images from the funeral of IRA murderer Tony Catney in west Belfast earlier this month to identify potential dissident republicans.
Armed and masked men fired a volley of shots in memory of Catney. Police have confirmed they are reviewing footage of the funeral.
Last year facial-mapping was used to identify a man wearing a balaclava and who was a flag bearer during a dissident parade. Patrick John McDaid, from Londonderry, was given a suspended prison sentence after being found to have managed a meeting in support of the IRA.
It was also used to jail a 21-year-old man, Tiernan Porter, for three years in relation to a paramilitary-style shooting in west Belfast.
Following Porter's conviction, PSNI Superintendent Glen Wright said: "Using specialist facial-mapping techniques we were able to identify that the person behind the mask was indeed the individual before the court, thereby placing the gun in his hand." Those heading up the hunt for Mr Foley's killer are hoping the technique can provide clues to the identity of the Muslim terrorist.
The four-minute film contained a wealth of other information, including the Islamic State of Iraq and the Levant killer's voice, his height and the fact he is left-handed.
He is also believed to have spoken with a south London accent. Investigators are trying to establish whether a voiceover was used in the video recording.