AMPATUAN, Philippines (AP) - Under threat of military attack, the scion of the clan suspected in the slaughter of 57 people in the southern Philippines turned himself, and prosecutors say he will face murder charges in the country’s worst election violence.

Andal Ampatuan Jr., a town mayor, maintained Thursday he had nothing to do with the ambush of a convoy carrying his political rival’s family, supporters and at least 22 journalists.

Their bodies - mowed down by point-blank shots Monday and some hacked up - were found in mass graves hastily dug by a backhoe. Some were buried with their vehicles.

The baby-faced 41-year-old is heir to the Ampatuan kingdom: impoverished, rural and lawless Maguindanao province, where they have ruled for years with a reputation for ruthlessness that led few to dare to challenge them. Hundreds of pro-government militiamen in their employ have been disarmed since the massacre.