As authorities expand their dragnet for ISIS members plotting new attacks in Europe and elsewhere, they are focusing on the potential role that female jihadists are playing in the terror network after one suspect died in an explosion in a confrontation with police.
Hasna Aitboulahcen died in a protracted gun and grenade battle with authorities in the Paris suburb of Saint-Denis on Wednesday as authorities raided the location in search of the suspected plot leader of the Paris attacks.
Described as a 26-year-old French-Moroccan national, Aitboulahcen died when a suicide vest detonated as police stormed the hideout where she was holed up with at least two Islamic State terrorists. One of them was believed to be her cousin, suspected plot leader Abdelhamid Abaaoud, 27, who also died during the seven-hour shootout.
Initial reports said that Aitboulahcen was carrying or wearing a suicide vest when she died, but on Friday police told French media outlets that she did not detonate a vest herself, but was killed when a third person detonated a suicide vest. NBC News could not immediately confirm those reports. If she was willingly wearing a vest, Aitboulahcen would be the first publicly known aspiring female suicide bomber in Western Europe -- for ISIS or any other terrorist organization.
Experts and officials said that the use of females as suicide bombers isn't new, but that it has been unusual for ISIS, which has stressed that women supporters mostly serve the male foot soldiers in the operation.
Lorenzo Vidino, an expert on the mobilization dynamics of jihadist networks in Europe and North America, described Aitboulahcen as a fully participating member of the terror plot and perhaps ISIS' broader network in Europe.
"She was active, she was known to intelligence as part of the milieu [of ISIS plotters], she was a cousin [of Abaaoud], she was plugged in," said Vidino, the director of the Program on Extremism at George Washington University's Center for Cyber & Homeland Security.
Aitboulahcen reportedly made comments on social media about wanting to go to Syria to join ISIS there, but apparently never made it. Somewhere along the line, she received training in the ways of jihad.
"She was quite active in the siege," Vidino said. "She certainly knew how to handle automatic weapons."
Witnesses said Aitboulahcen repeatedly called for help in what may have been an effort to draw police closer before detonating her vest, which was so powerful that it caved in the floor of the apartment complex.
"She knew what she was doing, obviously,'' said one U.S. intelligence official.
"I think she tried to coax the police into coming in so she could blow them up, but I don't think the police bought it," said the intelligence official, who spoke on the condition of anonymity because he was not authorized to discuss ongoing counterterrorism operations.
Authorities are also investigating whether Aitboulahcen -- described as a blonde-haired extrovert with a fondness for cowboy hats -- was firing an automatic rifle. And some authorities believe that she was involved in a suspected second wave of terror that Abaaoud had been planning. At least five other heavily armed suspects were believed inside the apartment at the time of the early morning raid.
Also under scrutiny: a tweet urging people to "support our sister," after the coordinated wave of terrorist attacks in Paris on Nov. 13 that killed at least 129 people. The Twitter account is believed to be associated with some members of the plot, and was posted the evening of the attacks.
Many terrorist organizations outside Western Europe have recruited and trained women as operational soldiers.
Those include the many "Black Widows" of the Chechen insurgency, including those at the Beslan school massacre and the siege of the Dubrovka theater in Moscow in 2002. "Women were part of the commando teams," said Vidino.
The idea of using women as suicide bombers is believed to have been conceived by the Tamil Tigers in Sri Lanka, and later used by Palestinian terror groups, especially Hamas, Vidino said.
But counterterrorism experts say that for all of its hostile actions toward woman, ISIS has also been surprisingly popular with women. Some estimates say one in 10 Europeans traveling to Syria to join the ISIS jihad are women, and they hold important -- but usually non-combat -- roles within the terror organization.
That's the case at the ISIS home base of Raqqa, Syria, but also within the group's online social media operation, which has had great success in recruiting, radicalizing and fundraising.
"They have been very successful at recruiting women," said J.M. Berger, co-author of the recent book "ISIS: The State of Terror." A counterterrorism consultant to government agencies, Berger said women play an especially important role on social media and in propaganda efforts. And in Raqqa, he said ISIS has a women's brigade that is responsible for enforcing morality on the women citizens. It's known as the Al Khansa Brigade, named after a historical Muslim poet who wrote about being proud to be the mother of martyrs, Berger said.
Audrey Alexander, a counterterrorism analyst, said ISIS recently has begun to embrace operational roles for women, and by doing so has followed the path of other terrorist organizations.
"There are no universal reasons why terrorist organizations allow, and sometimes encourage, women to participate in terrorism. Terrorist groups are increasingly likely to incorporate women as they come to realize that female attackers can more effectively evade detection," said Alexander, who wrote her dissertation about female terrorists and Western women's participation in ISIS.
"Organizations such as Islamic Jihad, al Qaeda, and Hamas revised earlier religious objections to female suicide bombers," she said, "opting instead to capitalize upon the sentiment of shock and awe."
As for why they would want to join a group like ISIS, Alexander said there are as many reasons for women as there are for men. They tend to be young. But other than that, "Much like male suicide bombers, female suicide bombers motives for participation are incredibly dynamic."