Paris Terror Attacks: Who is the mastermind of the massacre? What we know about Abdelhamid Abaaoud
Once a happy-go-lucky student at one of Brussels' most prestigious high schools, Abdelhamid Abaaoud has turned into Belgium's most notorious jihadi - so devoted to the cause that he recruited his 13-year-old brother to join him in Syria.
Abaaoud is the child of Moroccan immigrants who grew up in the Belgian capital's scruffy and multi-ethnic Molenbeek-Saint-Jean neighbourhood.
The fugitive, who is in his late 20s, was identified by French authorities on Monday as the presumed mastermind of the attacks in Paris that killed 129 people and injured hundreds.
Abaaoud is also believed to have links to earlier terror attacks that were thwarted: one against a Paris-bound high-speed train that was foiled by three young Americans in August, and the other against a church in the French capital's suburbs, according to officials.
"All my life, I have seen the blood of Muslims flow," Abaaoud said in a video made public in 2014. "I pray that Allah will break the backs of those who oppose him, his soldiers and his admirers, and that he will exterminate them."
Belgian authorities suspect him of also helping organise and finance a terror cell in the eastern city of Verviers that was broken up in an armed police raid on January 15, in which two of his presumed accomplices were killed.
The following month, Abaaoud was quoted by Islamic State's English-language magazine Dabiq as saying that he had secretly returned to Belgium to lead the terror cell and then escaped to Syria in the aftermath of the raid, despite having his picture broadcast across the news.
He boasted: "I was even stopped by an officer who contemplated me so as to compare me to the picture, but he let me go, as he did not see the resemblance!"
There was no official comment from the Belgian federal prosecutor's office about Abaaoud's reported role in the Paris attacks.
However, Belgian police announced the arrest of three suspects in Molenbeek over the weekend and were carrying out numerous searches there on Monday.
The area in the west of Brussels has long been considered a focal point of Islamic radicalism and recruitment of foreign fighters to go to Iraq and Syria.
Abaaoud's image became even grimmer after independent journalists Etienne Huver and Guillaume Lhotellier, visiting the Turkish-Syrian frontier, obtained photos and video last year of Abaaoud's exploits across Syria.
The material included footage of him and his friends loading a pick-up truck and a makeshift trailer with a mound of bloodied corpses.
Before driving off, a grinning Abaaoud tells the camera: "Before we towed jet skis, motorcycles, quad bikes, big trailers filled with gifts for vacation in Morocco. Now, thank God, following God's path, we're towing apostates, infidels who are fighting us."
Mr Huver told The Associated Press that the video was too fragmentary to say much about Abaaoud's character, but that he detected some signs the Belgian was moving into a leadership role.
"On the one hand I'm surprised," Mr Huver said of Abaaoud's prominence.
"On the other hand, I saw that there were beginnings of something. You can see that he's giving orders. You can feel a charismatic guy who's going up in the world ... You can see a combatant who's ready to climb the ranks."