MANILA - More bodies may still be buried at a mass grave in Ampatuan town, Maguindanao province where more than 50 people were massacred and dumped by gunmen allegedly loyal to the powerful political clan of the Ampatuans.

Commission on Human Rights (CHR) head Leila de Lima said an excavation team led by Jose Pablo Baraybar, a Peruvian forensic anthropologist, will resume excavation at a primary grave site in Barangay Saniag, Ampatuan town.

De Lima did not say when the excavation will resume. She said Baraybar has been deputized by the CHR to lead its forensic investigation.

She said Baraybar recommended the resumption of the excavation after noticing that there was an "untouched" portion of the primary grave site, where dozens of bodies were previously recovered, during a visit on Monday.

"He noticed that a portion is untouched and not fully excavated. It's a piece of land that is part of the primary grave site. In the interest of thorough investigation he said 'Let's do more digging," De Lima told radio dzMM.

Police have called off over the weekend the excavation after recovering 57 bodies from two grave sites in Ampatuan town. The site was almost two kilometers away from a highway in Maguindanao, where a convoy of the family of the Mangudadatu clan were stopped by at least 100 gunmen.

Among those killed were 22 women, including the wife of gubernatorial candidate Esmael "Toto" Mangudadatu and his two sisters, and at least 27 journalists.

De Lima said only two of the recovered bodies remained unidentified. She added that four families are claiming the two bodies, which, she said, suggest that there could be more bodies unrecovered.

She added that the CHR’s forensic team also smelled a strong stench from the site, which could not have been a remnant of the bodies previously recovered from the site.

De Lima said the forensic team also noticed uncollected items, such as shoes, slippers, a comb, a toothbrush, an ID and spent bullet shells, at the two mass graves. She said they will be collecting these items once they return to the site for the excavation.

The CHR chief said their excavation has been coordinated with the Department of Justice and all of the findings of their independent parallel investigation will be submitted to the government's investigating bodies for collaboration.

She said they also have authorized access to the findings of the police and the National Bureau of Investigation's (NBI) probe on the massacre.

Audio record

Mayor Mangudadatu told radio dzMM over the weekend that he asked one of her sisters to hide a tape recorder in her sock before the convoy left Buluan town.

The convoy, which included woman and journalists, was supposed to file a certificate of candidacy for governor on his behalf.

""I asked her to turn it on as soon as they left," Mangudadatu said. "It has a capacity of 288 hours or 12 days."

He said he has been informed by the police that they have recovered the recording device.

There was no independent confirmation of the presence of the recording. Police investigators have said they cannot reveal the details of some of the evidence they have collected.

The DOJ on Tuesday filed 25 counts of murder against Datu Unsay town Mayor Andal Ampatuan Jr. for the massacre. He is currently detained at the NBI headquarters in Manila.

Ampatuan Jr.'s father and 7 other members of the powerful political clan are also being suspected of having involvement in the massacre.

The massacre was allegedly ordered to stop Mangudadatu's formal filing of candidacy for governor of the province, a post held by the Ampatuans for several years.