LONDON: Police missed a golden opportunity to prevent the Paris terrorist attacks earlier this year when they allowed the ringleader to escape to Syria even though he was wanted for a series of murder plots.
Abdelhamid Abaaoud, a Belgian linked to several attacks in France, claims to have been stopped by an official who failed to recognise him.
It was one of a series of missed chances by the French and Belgian security services. One of the suicide bombers in Friday's attack, Samy Amimour, was on a watch list of suspected terrorists after attempting to travel to Yemen three years ago, but was able to get back into France from Syria undetected to take part in the attack on the Bataclan concert hall.
French officials have also confirmed that the US warned them in September that an attack was imminent, though the details were described as "vague".
The previous month, however, a man who was arrested before he could carry out orders from Abaaoud to attack "a concert hall" told police other attacks were imminent.
Abaaoud, 29, is said to have planned the Paris atrocities from Syria, where he is fighting with Islamic State of Iraq and the Levant (Isil). He is reported to have been on a list of targets for French air strikes since September.
Intelligence failures appear to have allowed Abaaoud to act with impunity.
He had travelled to Syria in 2013, then returned to Belgium via Greece. He was able to leave Belgium undetected and return to Syria, a round trip he made several times, he says.
Abaaoud is related to Ibrahim Abdeslam, one of the Paris suicide bombers, and in 2010 spent time in jail with Abdeslam's brother Salah, who has gone on the run. They are childhood friends, having grown up in the same suburb of Brussels.
Abaaoud's family had previously announced that he was dead, but police now think that claim was false.
He was the main target of a major police raid on a terrorist cell in Verviers, Belgium, in January in which two jihadists were killed. It was carried out within days of the Charlie Hebdo attacks in Paris, though police said the two events were not linked.
Earlier this year, he was sentenced to 20 years in absentia along with 32 other jihadists. The Belgian cell was said to have been planning a major terrorist attack, including abducting and beheading a prominent law enforcement official and posting a video of it online.
Police believe Abaaoud helped arrange a terrorist attack on an Amsterdam to Paris train on Aug 21, which was thwarted by four passengers including British businessman Chris Norman. The French newspaper Liberation claimed he was in contact with Ayoub El-Khazzani, the man who opened fire in a carriage of the train before he was overwhelmed by passengers.
He is also thought to have plotted an attack on a church in Paris on April 19, when Sid Ahmed Ghlam, a French IT student, was arrested after shooting himself in the leg. After following a trail of blood to a nearby vehicle, police found a car containing "an arsenal of weapons of war", according to the French interior ministry.
Ghlam was later charged with the murder of Aurelie Chatelain, a dance instructor who was found inside her own burning car after being shot three times in the head in what police thought was a bungled carjacking.
According to Le Monde newspaper, Abaaoud was also in contact with Mehdi Nemmouche, who killed four people in an attack on the Jewish Museum in Brussels in May 2014. Analysis of telephone calls is said to have shown the two men spoke in January 2014.
Le Monde also claimed a French
jihadist called Reda Hame, who was arrested on Aug 11, named Abaaoud as the man who had sent him to Europe to carry out a terrorist attack after he had been to Syria and trained for six days in Raqqa, the Isil stronghold.
He said Abaaoud told him to travel via Prague to avoid being detected and gave him a USB stick containing encryption software and euros 2,000 (pounds 1,400) with instructions to hit an "easy" target such as "a concert hall" to ensure the "maximum number of victims".
Asked whether other attacks were in the pipeline, Hame told police: "All I can say is that this will happen very soon. It was a real factory out there and they will really try to hit France and Europe."
A source close to the French investigation into Abaaoud said of him: "He appears to be the brains behind several planned attacks in Europe." Earlier this year Abaaoud boasted in an Isil magazine about masterminding terrorist plots under the noses of the Belgian security services before returning to Syria.
Abaaoud, who uses the alias Abu Omar Al-Baljiki, told Dabiq magazine: "I was able to leave... despite being chased after by so many intelligence agencies. All this proves that a Muslim should not fear the bloated image of the crusader intelligence.
"My name and picture were all over the news yet I was able to stay in their homeland, plan operations against them, and leave safely when doing so became necessary." He said he and two fellow jihadists travelled to Belgium to "terrorise the crusaders waging war against the Muslims".
He said: "We faced a number of trials during the journey. We spent months trying to find a way into Europe, and by Allah's strength, we succeeded in finally making our way to Belgium.
"We were then able to obtain weapons and set up a safe house while we planned to carry out operations against the crusaders." Abaaoud said he was stopped during the journey by "an officer" after a picture of him fighting for Isil was published in Belgian media, but the officer "let me go, as he did not see the resemblance". He did not say when or where he was stopped.
He boasted that he had been able to plan terror attacks against Westerners while living in Belgium and being wanted by intelligence agencies when he travelled to Syria in January 2014.
Abaaoud was described as a happy-go-lucky student who went to one of Brussels' most prestigious high schools, Saint-Pierre d'Uccle.
As a boy growing up in the Molenbeek district of Brussels he played with Salah Abdeslam, who is now wanted by police in connection with the Paris attacks.
His father, Omar, is a grocer there and he is reported to have taken his 13-year-old brother, Younes, with him to Syria in January 2014.
Abaaoud has been used as a major recruiting tool by Isil to attract other Belgians to the terrorist network.
He enjoys boasting about his exploits, appearing in an Isil video smiling at the wheel of a pick-up truck taking eight mutilated bodies to a mass grave.