MANILA, Philippines - The Abu Sayyaf Islamic militant group has terrorised the southern Philippines and nearby areas with a trail of bombings, kidnappings and beheadings since the 1990s.
Retired Italian Catholic priest Rolando Del Torchio, believed to have been kidnapped by the Abu Sayyaf six months ago, was released on Friday on a remote island infamous as a stronghold of the group.
The following is a timeline of the Abu Sayyaf's rise and rampage:
-- Early 1990s: Libya-trained preacher Abdurajak Janjalani forms the Abu Sayyaf (Bearer of the Sword) with young Muslims disaffected by an older generation of guerrillas.
The new group is backed by seed money from a local charity run by Mohammad Jamal Khalifa, a brother-in-law of Al-Qaeda chief Osama bin Laden.
-- April 4, 1995: Hundreds of its gunmen sack the southern town of Ipil, leaving more than 50 people dead.
-- December 18, 1998: Janjalani is killed in a clash with security forces on the island of Basilan and is replaced by younger brother, Khadaffy Janjalani. He is killed in September 2006.
-- April 23, 2000: The group makes its first known foreign sortie, snatching 10 Western tourists and 11 Asians from the Sipadan island resort, off Malaysian Borneo.
The hostages are freed in August 2001, with the westerners flown to Tripoli aboard a jet sent by then Libyan leader Moamer Kadhafi, who is said to have paid millions of dollars in ransom.
-- May 27, 2001: Three Americans are among 20 people snatched from a western Philippine island resort. One of them, tourist Guillermo Sobero, is beheaded 13 months later. Most of the local hostages are ransomed off.
One of the other Americans, Christian missionary Martin Burnham, and a Filipina hostage are killed in a military operation in June 2002. But Burnham's wife is rescued.
-- February 27, 2004: The Abu Sayyaf firebombs a ferry on Manila Bay, killing 116 people in the country's deadliest terrorist attack.
-- March 15, 2005: Philippine police crush a violent overnight riot at a Manila prison, killing 17 Abu Sayyaf men including four leaders standing trial for the Sipadan kidnappings and the ferry bombing.
-- July 10, 2007: The Abu Sayyaf and fighters from the mainstream guerrilla group Moro Islamic Liberation Front kill 14 Filipino marines on Basilan, beheading 10 of them.
-- December 5, 2011: The Abu Sayyaf abducts Australian ex-soldier Warren Rodwell at his southern Philippine home. He is freed unharmed in March 2013 after a reported ransom of nearly $100,000 is paid.
-- February 1, 2012: Two bird watchers, a Dutchman and a Swiss, are abducted in the Tawi-Tawi island group. The Swiss escapes from the Abu Sayyaf in December 2014.
-- April 25, 2014: German couple Stefan Okonek and Henrike Dielen are abducted while aboard a yacht sailing off the western island of Palawan. The couple are ransomed off six months later.
-- Sometime in mid-2014: Isnilon Hapilon, who has a $5-million bounty on his head by the US government, becomes the first of several senior Abu Sayyaf leader to pledge allegiance to Islamic State jihadists fighting in Iraq and Syria.
-- May 14, 2015: Malaysian tourist Bernard Then and restaurant manager Thien Nyuk Fun are seized in the Malaysian port of Sandakan.
The woman is released in November, reportedly after a ransom was paid. But the Abu Sayyaf beheaded the man as Malaysian Prime Minister Najib Razak was in the Philippines attending a regional summit.
-- September 21, 2015: Canadian tourists John Ridsdel and Robert Hall, Norwegian resort manager Kjartan Sekkingstad, and Hall's Filipina girlfriend are seized from yachts docked at a resort on Samal island, hundreds of kilometres from the Abu Sayyaf strongholds.
Last month the kidnappers set an April 8 ransom deadline, threatening to behead the hostages. The deadline passes with no word about their fate.
-- October 7, 2015: Del Torchio is kidnapped at his pizza restaurant on the southern city of Dipolog, also far from the Abu Sayyaf strongholds. Though no group claimed responsibility, security analysts say the Abu Sayyaf is likely responsible.
-- March 26, 2016: Ten Indonesian sailors are seized as their tugboat pulls a barge carrying coal off Malaysian Borneo. The vessel's owners say the Abu Sayyaf has demanded a ransom.
April 1, 2016 -- Gunmen on speedboats seize four Malaysians from the east coast of Sabah state. The Malaysian authorities describe the gunmen as Filipino.
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