DAVAO CITY - An Arabic-speaking preacher with an engineering degree from the Philippines' top university, Isnilon Hapilon, 51, is one of the world's most wanted terrorists.
Hundreds have died and millions have been spent in the hunt for the Abu Sayyaf chieftain designated by the Islamic State in Iraq and Syria (ISIS) as its top man in South-east Asia last year.
But he remains elusive.
Hapilon moved out of the Abu Sayyaf's strongholds in Sulu province last year to bring bandit and terrorist groups in the southern Philippines under ISIS' banner.
He gained notoriety in 2001 when he took part in the kidnapping of 20 hostages from a resort in Palawan province. He rose up the ranks of Abu Sayyaf to become its second in command.
The United States considers him to be one of the world's most dangerous terrorists and offers US$5 million (S$6.9 million) for his capture.
Hapilon has had close shaves over the years, but managed to escape large-scale military operations to capture him in 2008 and 2013. The latest close call came in January, when the military dropped bombs on a militant camp where Hapilon was seen.
This week, after receiving intelligence that Hapilon was in Marawi for medical treatment, the military launched a raid on an apartment where he was believed to be hiding. But the troops were thwarted by gunmen from the Maute group
Not only did Hapilon escape yet again, but the gunmen also went on a rampage in the city, holding various hostages as human shields.
Most of Marawi's 200,000 residents have since been evacuated, with President Rodrigo Duterte imposing martial rule across the southern island group of Mindanao, home to over 20 million people.