Philippine police said they arrested on Tuesday a member of an Al Qaeda-linked extremist group who was involved in the kidnapping of an American couple a decade ago.
The suspect, known as "Abu Ismael", a member of the Abu Sayyaf militant organisation, was seized on the remote southern island of Basilan, said island police chief Alexis Lineses.
"Abu Ismael was one of the armed guards during Grace (and) Martin Burham's captivity in Basilan," Lineses said, referring to the two Americans.
The Burnhams, an American missionary couple, were kidnapped along with Chilean-born American Guillermo Sobero by the Abu Sayyaf from a resort in the western Philippines in 2001.
Abu Sayyaf militants beheaded Sobero while Martin Burnham was killed in a rescue attempt in 2002 that recovered his wife alive.
The suspect was also trained in bomb-making and helped scout out kidnapping targets for the Abu Sayyaf, according to Lineses.
The Abu Sayyaf is the most infamous of many Muslim militant groups known to carry out such kidnappings for ransom in the south.
The group was founded in 1990 with Al Qaeda funding and has been blamed for the Philippines' worst terrorist attacks, including a ferry bombing that killed more than 100 people in 2004, as well as the beheadings of foreigners.
Various Abu Sayyaf factions are also believed to be holding Australian Warren Rodwell, kidnapped in December, along with an Indian national, two Malaysians, a Japanese and three Filipinos all seized since 2010.
A rotating force of about 600 US soldiers has been stationed in the southern Philippines for a decade to train the Philippine military how to fight the Abu Sayyaf group.