MANILA, Philippines?(UPDATE 6) Datu Unsay mayor Andal Ampatuan Jr. has been formally charged with multiple murder before the Department of Justice over Monday?s slaughter of at least 57 people in Maguindanao.

Justice Secretary Agnes Devanadera said a panel of prosecutors handling the case would issue a resolution within 36 hours with regards to filing of the formal complaint before the court in Maguindanao.

Chief State Prosecutor Jovencito Zuño, who along with Devanadera, performed the inquest at the General Santos City airport Thursday, said that seven counts of multiple murder would be filed against Ampatuan.

He explained that more would be filed against the prime suspect in the grisly slays as son as they get more medico legal reports.

Ampatuan was flown to Manila and now in the custody of the National Bureau of Investigation to face charges he led a pack of about 100 gunmen in the pre-election violence that sent shock waves around the world. If proven guilty in court, he will be jailed for life without possibility of parole.

Ampatuan, scion of a powerful clan in central Mindanao, is the prime suspect in the carnage Monday morning when political rival Buluan Mayor Esmael Mangudadatu? through his wife and supporters?was set to file his certificate of candidacy for Maguindanao governor.

Tension rose at the airport as Mangudadatu came face to face and pointed an accusing finger at the prime suspect in the grisly slays. Mangudadatu?s wife Genalyn, his sisters, and other relatives were among those killed and dumped in shallow graves.

During the closed-door inquest proceedings at the airport VIP lounge, Mangudadatu affirmed his affidavit.

But the son of Maguindanao governor Andal Ampatuan Sr. insisted he did not orchestrate the horrifying killings.

"There is no truth to that," Ampatuan Jr. told reporters at the airport when asked whether he was behind the murders.

It was his first public comment since the massacre and was made after authorities took him into custody from his home and flew him by helicopter to General Santos City, from where he was set to be flown to Manila.

Interior Secretary Ronaldo Puno earlier told reporters in Manila that witnesses to Monday's massacre would also be brought with Ampatuan Jr. to Manila to help authorities in their investigations.

Officials had been negotiating since Tuesday with Ampatuan's powerful family for him to submit to questioning.

The massacre occurred after about 100 Ampatuan gunmen allegedly abducted a convoy of aides and relatives of Mangudadatu, plus a group of journalists.

The victims were snatched as they were traveling in a six-vehicle convoy to nominate Mangudadatu as the opposition candidate for provincial governor in next year's elections.

They were shot at close range, some with their hands tied behind their backs, and dumped or buried in shallow graves on a remote farming road close to a town bearing the Ampatuan name.

Fifty-seven bodies have been recovered so far, 18 of whom were journalists.

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

Maguindanao is part of the Autonomous Region in Muslim Mindanao, 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.

In Manila, Puno said all the police from Ampatuan town were being investigated amid suspicions they were involved in the massacre.

"All members of the Ampatuan police station are under investigation for complicity in the crime," he said.

However, indicating the situation in Maguindanao province remained extremely volatile, the military said most of the Ampatuan family's militiamen alleged to have carried out the massacre were still on the run.

"Most of the armed group that perpetrated this crime have run away towards the mountainous area of Maguindanao," military spokesman Lieutenant Colonel Romeo Brawner said on ABS-CBN television.

"That is where we are conducting our pursuit operations."

The ruling Lakas Kampi CMD coalition late on Wednesday expelled both Ampatuans from the party.

Ampatuan Jr.?s brother, Zaldy, governor of the Autonomous Region in Muslim Mindanao that includes Maguindanao, was also expelled.

"(They were) expelled for their failure to uphold party ideals and principles in their area of jurisdiction," the coalition's nomination for president in next year's elections, Gilberto Teodoro, said in a statement.