MANILA, Philippines ? The massacre in Maguindanao province has ?many witnesses, not just one? and their testimonies pointed to a common perpetrator, Justice Secretary Agnes Devanadera said Friday.

"We have many witnesses, not just one" and that they told prosecutors that Datu Unsay mayor Andal Ampatuan Jr. ordered his private militia of more than 100 gunmen to open fire on the group of people on a remote farming area in the southern Philippines.

Devanadera issued the statement, a day after Al-Jazeera posted on its news website an interview of supposedly one of the gunmen in the November 23 carnage.

The gunmen had a short time earlier abducted a convoy of aides and relatives of a rival Muslim politician, Esmael Mangudadatu, plus a batch of local journalists.

The group had been traveling to an election office so Mangudadatu's wife, Genalyn, could nominate the Buluan mayor to run against Ampatuan Jr. for the post of Maguindanao governor in next year's elections.

Fifty seven bodies have since been recovered from shallow graves in the killing fields close to a town bearing the Ampatuan name.

At least 22 of the victims were women, police said earlier.

Twenty-seven victims were journalists and 15 were motorists who were driving past the area at the wrong time, all of whom were apparently killed to eliminate witnesses.

In the most detailed account yet of Monday's election-linked massacre, which has sent shockwaves through the Southeast Asian nation, Devanadera said female victims may have also been raped.

"It was horrible. I cannot begin to describe it," Devanadera told GMA television network?s morning show ?Unang Hirit,? recounting what she had seen of the bodies as well as the testimony of many of those who had taken part in the killings.

Ampatuan Jr., who surrendered to authorities on Thursday and was taken to Manila where he was expected soon to be charged with mass murder, has denied any involvement and blamed Muslim rebels for the killings.

But Devanadera said many of those who took part in the massacre were clear that Ampatuan Jr. was at the scene of the murders, ordered them to open fire and even shot people himself.

"The order was to kill them all... it appeared premeditated," she said.

"One of the witnesses said he [Ampatuan Jr. was the one who was ordering them... another witness saw him firing his gun as well."

Devanadera said some of those who took part in the killings, or were ordered to be involved, had come forward because of the guilt they felt.

"They were bothered by their conscience," she said, while emphasizing many of them had given testimony against their former boss.

She said the group of more than 100 gunmen included soldiers and policemen.

Authorities had said that hundreds of policemen believed loyal to Ampatuan's powerful clan in Maguindanao province had been detained and suspected of being directly involved or linked to the massacre.

Devanadera painted a gruesome picture of the fate of the women at the hands of the marauding militia.

"Even the private parts of the women were shot at. It was horrible. It was not done to just one. It was done practically to all the women," she said.

"All the women had their zippers undone. The pants of some were pulled down... We have yet to determine whether they were raped. But it is certain that something bad was done to them."

Devanadera said charges of multiple murder were likely to be filed later on Friday.

"They will ask the court for Ampatuan Jr. to be denied bail. I don't see how he could get out of jail at this time, with the kind of evidence that we have," she said.

Ampatuan Jr. is the son of Maguindanao's governor, a Muslim clan chief of the same name who until this week was a close ally of President Gloria Macapagal-Arroyo's ruling coalition.

Maguindanao is part of Mindanao Island, where Muslim clans rule vast areas backed by their own private armies, often out of the national government's control.

Ampatuan Sr. had been grooming his son, currently a local mayor, to take over as governor of Maguindanao. The victims' relatives alleged the Ampatuans organized the murders so that Mangudadatu would not run for that post.