Prosecutors in the Philippines have now charged a provincial governor in connection with last month's massacre on the southern island of Mindanao.
The killings in Maguindanao province left 57 people dead, following an ambush on a convoy of political campaigners and accompanying journalists.
The convoy had been on its way to file campaign papers for a candidate challenging the incumbent governor in elections next year.
Al Jazeera has gained exclusive access to a witness saying the powerful clan leader masterminded the massacre.
Marga Ortigas reports from Manila.
