NEW : Authorities did not identify Ampatuan as a suspect . The Philippines is one of the world's most dangerous countries for journalists and human rights activists. Ampatuans hold leadership positions in Mindanao . Authorities disband paramilitary force in the southern Philippines .
NEW : Authorities did not identify Ampatuan as a suspect . Datu Unsay mayor led group that initially stopped civilians , police cite reports as saying . Ampatuans hold leadership positions in Mindanao . Authorities disband paramilitary force in the southern Philippines .