MANILA - A Singaporean Islamic militant was killed in clashes in December that intelligence officials here believe may have led to a deadly bombing in the war-torn southern Philippine island of Mindanao.
A senior military official identified the Singaporean as Abu Hud Zain. It was not clear whether this was his real name or just an alias.
Investigators had yet to recover his passport or any documents to confirm his identity, according to the official, who asked not to be named because of the nature of the information he was sharing.
Zain was killed in covert operations by security forces in Mamasapano town, in Maguindanao province, on Dec 22.
He died with an Indonesian, Abdulrahid Ruhmisanti, and Filipino brothers Salamuddin and Mohammad Hassan.
This happened about a week before a bomb went off in front of a shopping mall in Cotabato city on Monday (Dec 31), killing two and wounding dozens.
Major-General Cirilito Sobejana, chief of the 6th Infantry Division, told reporters the attack was probably a retaliation for the deaths of the four militants.
Zain was said to be part of the Muhajireen Wal-Ansar, also known as the Maguindanao Daulah Islamiyah, a faction of the Bangsamoro Islamic Freedom Fighters (BIFF) under the firebrand preacher Esmael Abdulmalik, also known as Abu Turaife.
BIFF is a splinter group of the 12,000-strong Moro Islamic Liberation Front (MILF), the main secessionist group that has been holding peace talks with the government. It was carved out of the MILF's 105th Base Command, under Ameril Umbra Kato.
Kato had refused to participate in "endless peace negotiations and forever ceasefire", and instead sought a more hardline approach and linked up with the Islamic State in Iraq and Syria (ISIS).
Intelligence officials said the Turaife group, consisting of about 150 militants, had been roaming a sprawling marshland from North Cotabato province to Maguindanao.
It has been providing shelter to ISIS fighters across South-east Asia, the Middle East and North Africa, they said.
The Hassan brothers were sons of Salahuddin Hassan, once a top lieutenant of Kato.
The elder Hassan and three others - Bashir Ungab, Nasser Adil and Ansari Yunos - broke off from the main BIFF group due to infighting after Kato's death and chose Turaife as their leader.
BIFF had since split into three factions: Abu Turaife's and those led by Imam Bongos and Imam Karialan.
Over a thousand militants aligned with ISIS stormed and laid siege to the southern Islamic city of Marawi in May 2017, sparking five months of intense fighting and military airstrikes that left more than 1,100 people - mostly militants - dead and displaced hundreds of thousands of villagers.
Security officials have said remnants of the militant groups behind the siege have fled to remote areas where BIFF has been operating freely.
Maj-Gen Sobejana said the bombing in Cotabato could also be intended to derail a plebiscite set for this month to ratify a long-awaited law to allow minority Muslims in Mindanao to start moving toward self-rule by 2022.
The Bangsamoro Organic Law is the culmination of a lengthy and rocky peace accord with the MILF. But militants oppose it, as they insist instead on carving out an ISIS "province" in Mindanao.
"There is a strong indication that the attack is, in a way, political in nature," said Ms Sidney Jones, director of the Jakarta-based Institute for Policy Analysis of Conflict and an expert on terrorism in South-east Asia.
But Ms Jones believes the blast may have been meant to send a message to the Sayadi family, who are currently in power in Cotabato city.
Mayor Cynthia Guiani-Sayadi has predicted Cotabato city will likely reject the Bangsamoro law.