The killers in Paris wore suicide vests because they intended to die. All of them blew themselves up except the one who was killed before he could. Why? They believed they were martyrs going to an eternal paradise to feast with Allah, enjoy flowing rivers of wines and eternal virgin girls.
They did not believe this because some leader in ISIS or Al kata originated the idea. They believed it because the Koran declares it. And they believed this Koran was written by God, the God Allah. Men do not die for doubt. They blew themselves up with absolute assurance they were on their way to heaven as a reward for killing infidels. They had the same assurance the 9/11 killers had, that the virgins were waiting for them. Their assurance came from the Koran, the root source of their killings.
ISIS and other terrorists organizations are propagating this teaching about martyrdom, however they did not originating it. The Koran is the originator.
Anywhere the Koran is taught there will be a few who will fully believe it and obey this. These will kill non-Muslims with or without being members of a terrorist organization.