Militants holding two Canadians, a Norwegian and a Filipina as hostages in the southern Philippine island of Mindanao are believed to be led by a college-educated, social media-savvy fellow fanatic keen on transforming the Abu Sayyaf extremist group from a band of criminals into a bona fide Islamist movement.
A video showing the hostages begging for their lives, as masked men stood behind them displaying a black Islamic State in Iraq and Syria (ISIS) flag, confirms that the Abu Sayyaf's "Tanum sub-group" is responsible, according to international security analyst Rommel Banlaoi.
The group is named after a village in Patikul town, in Sulu province - 1,400km south of the capital Manila - where it draws most of its fighters. It is led by Hatib Sawadjaan, whom the military believes commands at least 300 men.
The Tanum group's chief planner is Sawadjaan's right-hand man, Muamar Askali, reportedly an apprentice of Bali bomber Umar Patek.
Another analyst, who declined to be named because he still consults for the military, said while Abu Sayyaf chieftain Isnilon Hapilon would rather stay in his safe havens in Sulu and nearby Tawi Tawi island, Askali is keen on expanding the Abu Sayyaf's reach and elevating the group's profile into a legitimate ISIS affiliate.
The four hostages - Canadians Robert Hall, 50, and John Ridsdel, 68; Norwegian Kjartan Sekkingstad, 56; and Filipina Maritess Flor, 40 - were taken on Sept 21 from a resort on Samal Island, off Davao city.
Security officials initially doubted the Abu Sayyaf's involvement because Samal is over 800km away from Sulu, far from their usual hunting grounds around Malaysia's Sabah state and the Zamboanga peninsula in Mindanao.
A task force created to go after the hostage takers had suggested communist rebels might have been behind the abduction.
In the video, which the military conceded could be authentic, a masked man demanded in fluent English that the military stop its operation to rescue the four hostages.
The man is said to be Askali. He has been described as a "rising star" and a "true believer" among Filipino extremists. A one-time criminology student, he is supposedly valued within the Abu Sayyaf for his family ties with several policemen.
Askali reportedly planned the abduction of two German nationals off Sabah in April last year. They were released six months later after the German government paid 250 million pesos (S$7.5 million).
But for defence analyst Jose Antonio Custodio, suggestions that the Abu Sayyaf is evolving ideologically is rubbish. "They're using the ISIS flag not because they really believe in it. They're actually trying to get more support from abroad. They're just after money… They're still basically merchants," he said.