Officials also confirmed that his cousin was killed, when she apparently blew herself up.
Abdelhamid Abaaoud, 27, had been linked to as many as four thwarted attacks since this spring, including the plot to kill passengers on a Paris-bound high-speed train in August, a plot that three young Americans helped foil. He was identified from skin samples after the Saint-Denis apartment raid, the French prosecutor's office reported.
Later Thursday, police in the eastern French city of Charleville-Mezieres blew open a door to enter a house during a new raid.
French police are looking for anything that could be linked to jihadi networks or illegal weapons. Police spokeswoman Mathilde Coulon would not give further details about the Thursday evening raid.
Abaaoud had claimed he successfully moved back and forth from Europe to Syria coordinating terror attacks, and narrowly escaped a January police raid in the Belgian city of Verviers. “Allah blinded their vision and I was able to leave... despite being chased after by so many intelligence agencies," he told the ISIS magazine Dabiq.
Two counterterrorism sources tell Fox News his death marks a major advance for the investigation, but add they are operating on the premise that more senior suspects connected to the plot are still out there.
They describe Abaaoud as the “Mohammed Atta” of the Paris attacks, the “tactical guy” who identified and pulled together the operatives, in the same way the lead hijacker kept the 9/11 teams on course.
They emphasize that based on his skill set and experience, Abaaoud was not the strategic planner, in the same way Khalid Sheikh Mohammed was for the 9/11 attacks. The Paris massacre involved a plot or plots with multiple layers and upwards of 20 players, according to the chairman of the House Homeland Security Committee, Texas Republican Michael McCaul.
Police say they launched Wednesday's operation after receiving information from tapped phone calls, surveillance and tipoffs suggesting that Abaaoud was holed up in the apartment. Investigators said it was still unclear how he died. Eight other people were arrested.
French authorities did not know he was in Europe before the massacre, France's interior minister Bernard Cazeneuve said Thursday. He demanded Europe do everything in its power to "vanquish terrorism."
During the raid, according to one police official, an officer approached Abaaoud's cousin, Hasna Aitboulahcen, and asked her, "Where is your boyfriend?" She responded angrily: "He's not my boyfriend!" Then there was an explosion.
The bodies recovered in the raid were badly mangled, with a part of the woman's spine landing on a police car, complicating formal identification. Her possible role in the Paris massacre was unclear.
Abaaoud's death may provide some relief not only for Europeans, but also for his own family. “We are praying that Abdelhamid really is dead,” his sister, Yasmina, said last year, The New York Times reported. At the time, there was word he died fighting for ISIS, but it eventually emerged that he escaped Syria for Europe.
His own father, Omar, said the jihadi "dishonored" his family, the Times added.