Attacker i Paris, 2015-11-13

Abaaoud, an ardent Islamic State supporter linked to several other terrorist attempts, was believed to be in Syria earlier this year. But some officials speculate he could have returned to Europe, perhaps passing undetected among the flood of asylum seekers pouring into Greek islands from Turkey.

The siege appeared to have been aided by another potential breakthrough in the probe: the discovery of a mobile phone in a garbage can near the Bataclan Concert Hall, the site of one of Friday’s assaults.

The phone’s data contained a map of the music venue, French media reported, along with a chilling text message sent shortly after the first gunmen entered: “Let’s go, we’re starting.”

The information on the mobile phone opened fresh leads, including to an apartment southeast of Paris in Alfortville, according to Mediapart, a French news outlet.

Lotfi, a 50 year old who was in the area, told Le Parisien : "I heard police officers talking to a woman with long blonde hair.

"I think she was the suicide bomber. They told her not to lower her arms, to keep her hands up in the air, and then there was a massive explosion.

"I think that’s when she detonated her bomb. It really was a very loud explosion.