Sources said if Usman had really been killed, then al-Qaeda ties with the Abu Sayaf
group could be proved.
Increased US involvement in the Philippines, where extremist Muslim separatist group Abu Sayaf
is fighting a guerrilla war, has heightened the concern.
It was supplied to the Indonesia-based Islamic Moro Front, which is linked to bin Laden and also to Abu Sayaf
, the terrorist group trying to establish a breakaway fundamentalist Muslim regime in the Philippines.
Macrohon is allegedly one of the biggest suppliers of illegal drugs in Barangays Boton and Languyan in Mohamad Ajul municipality, an area in Basilan province known to be protected allegedly by Abu Sayaf
He is said to be the appointed emir (leader) of the Islamic State in Southeast Asia replacing Abu Sayaf
leader Isnilon Hapilon who was killed in the five-month war in Marawi.