Police said Friday that they were tipped off to Sahid Guiamadel’s identity by his brother, who is seeking a reward offered by authorities for the capture of any of the more than 100 suspects still at large.

Leaders of a politically powerful clan and several of their lieutenants have been put on trial over the massacre.

They are accused of leading an ambush of a convoy and killing at least 57 people, including political opponents and media workers who accompanied them.

Police Director Samuel Pagdilao said Guiamadel was arrested Wednesday at the Cotabato Provincial Hospital.