The world's most notorious terrorist, so-called Jihadi John, has been linked to the Banbridge-born 'White Widow' - and may have been travelling to meet her when first stopped by the intelligence services.
Mohammed Emwazi has been identified as the masked executioner responsible for beheading a number of western hostages.
It has emerged Emwazi reportedly made attempts to join the al-Shabaab terror group in Somalia.
One of its leaders is believed to be Samantha Lewthwaite, the widow of one of the July 7 London bombers,
Mother-of-four Lewthwaite is currently the most wanted female terror suspect in the world.
The Islamic terror group al-Shabaab carried out a massacre at a Kenyan shopping centre in September 2013 in which more than 60 people were killed. The 30-year-old converted to Islam in her teens after leaving Northern Ireland.
Lewthwaite is wanted on charges dating back to 2011 which include being in possession of explosives and conspiracy to commit a felony. She has been on the run since.
According to The Sunday Times, Emwazi (26) was part of a network of Britons trained by Fazul Abdullah Mohammed, al-Qaida's former leader in Africa, before heading to Syria.
Mohammed is thought to have been a "patron" of Lewthwaite.
A Whitehall source told the paper Emwazi was also connected to a radical preacher who set up a prayer group in Greenwich which was attended by the killers of Fusilier Lee Rigby. Emwazi and another man were detained by the security services while in Tanzania in 2009.
After being questioned, he flew to Amsterdam where he was reportedly met by M15.
He went to Syria in 2012 where he joined so-called Islamic State. Emwazi was last week identified as the man who first appeared in an August 2014 IS video seemingly showing him murdering US journalist James Foley.
He was later seen in similar footage showing the beheadings of two Americans - journalist Steven Sotloff, US-aid worker Abdul-Rahman Kassig - and two Britons - aid worker David Haines and taxi driver Alan Henning.
Emwazi is said to have been on the radar of the British intelligence services for six years.