Andal Ampatuan Jr (right) is accused of ordering and leading the killings
A member of a powerful clan accused over a massacre of 57 people in the southern Philippines has been charged with multiple murders, prosecutors say.
Andal Ampatuan Jr, a mayor from lawless Maguindanao province, surrendered last week and has denied involvement.
Prosecutors say witnesses saw him lead gunmen in the 23 November massacre.
Those killed were trying to file nomination papers for a candidate challenging Mr Ampatuan in next year's elections for governor.
The group - which included relatives of the candidate, lawyers and journalists - were taken to a remote hill region and shot at close range.
Their bodies were then dumped in shallow graves.
Elections in the Philippines are often hit by violence but this incident has horrified the nation.
President Gloria Arroyo has promised that the killers will be brought to justice.
The BBC's Danny Vincent in Manila says the Ampatuan family are close allies of the Mrs Arroyo, but since the murders several family members have been removed from her party.
Prosecutors say that Andal Ampatuan Jr has been charged with 25 counts of murder and that 10 witnesses are likely to testify against him.
The charges have been filed in Cotobato city, in the closest regional court to the massacre site.
But prosecutors are expected to ask for the trial to be moved to the capital, Manila, for security reasons.
About 20 other suspects, including senior members of the Maguindanao provincial police force and officers of Ampatuan township's force, are in custody and are being investigated.
The Ampatuan family have effectively been in charge of Maguindanao for decades, analysts say.
Andal Ampatuan Sr has served in the Philippines Congress and won the governorship of Maguindanao unopposed for several terms.
His son was reportedly planning a similarly unopposed run to replace his father when Ismael Mangudadatu decided to contest the office.
Mr Mangudadatu's wife, his two sisters and several key supporters were among the dead.