KIDAPAWAN CITY -- Grenades were lobbed Sunday near the mansion of former Maguindanao Governor Andal Ampatuan Sr. whose son, Andal Jr., will be tried Tuesday for the massacre of 57 people in the southern province.

Authorities said some of the 160 suspects in the Maguindanao massacre, which happened last November 23, 2009, are now hiding in Davao Region to evade arrest, and the attack Sunday on the mansion of the Ampatuans were allegedly perpetrated by Moro Islamic Liberation Front (MILF) rebels.

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Superintendent Alex Lenesis, acting provincial director of the Maguindanao Provincial Police Office, said the suspects pounded with 40 mm grenade projectiles at the residential compound of the Ampatuan clan in Shariff Aguak, prompting many residents of the town to flee their homes.

There have been reports that the MILF rebels were planning to attack the Ampatuan mansions. But Eid Kabalu, MILF spokesperson, denied the Moro rebels had any plan of attacking the Ampatuan mansions or the civilians in Shariff Aguak.

Instead, Kabalu blamed some Civilian Volunteer Organization (CVO) members who were not paid by the Provincial Government, or those seeking firearms hidden by the Ampatuans.

The authorities found three shoulder-fire grenades lobbed near Andal Sr.'s house and two more grenades landed near the gasoline station owned also by the Ampatuans in the Sunday's incident. No one was hurt.

The projectiles, according to Lenesis, landed near a private mosque of the Ampatuans.

The incident happened hours after armed men robbed houses in nearby villages, taking along with them three motorcycles they used as getaway vehicles. One of the three stolen motorcycles, however, was recovered by the police Monday, said Lenesis.

Lieutenant Colonel Jonathan Ponce, regional Army spokesperson, said additional troops have already been deployed in Shariff Aguak and nearby towns to provide security to the residents.

Lenesis also said that Shariff Aguak had enough Army and police personnel to secure the Ampatuan mansions and the civilians from harassment of MILF or other lawless groups.

While police and military personnel are on heightened alert in Maguindanao, all state prosecutors in Manila are all but ready for the trial Tuesday of Andal Jr., the primary suspect in the Maguindanao massacre, before the Quezon City Regional Trial Court (QC-RTC).

The Department of Justice (DOJ) has so far filed 56 counts of murder against the Datu Unsay town mayor, with one more massacre victim still unidentified by investigators.

The hearing for bail, to be presided by Judge Jocelyn Solis-Reyes of QC-RTC branch 221, will start at 8:30 a.m., with the arraignment of the accused, followed by the presentation of the prosecution's evidence.

The DOJ team will be led by Chief State Prosecutor Jovencito Zuno, Assistant Chief State Prosecutor Richard Anthony Fadullon, Senior State Prosecutor Leo Dacera, State Prosecutors Juan Pedro Navera, Rassendell Gingoyon and Liezel Morales, Associate Prosecution Attorneys Xerxes Garcia and Mary Jane Sytat.

Fadullon told reporters that the prosecution will present its witnesses before the court to show that the evidence of guilt against Ampatuan is strong. However, he did not disclose how many witnesses they have and what they will testify about.

Tuesday's hearing will be divided into two parts: the petition for bail filed by Ampatuan's lawyers and their petition to show cause on why he was brought to the DOJ preliminary investigation last December 18.

Defense Counsel Philip Sigfrid Fortun sought bail for Ampatuan, even though murder is a non-bailable crime, alleging that the evidence of the prosecution against his client came from polluted sources that may have axes to grind.

Fortun also filed a motion to issue a show cause order on why the DOJ insisted on bringing Ampatuan to the December 18 preliminary investigation, thereby unnecessarily exposing him to the wrath of some reporters who went to cover the proceedings.

But Fadullon said the DOJ panel already filed its comment to the motion, explaining that there was no conspiracy to intentionally hurt Ampatuan. He said security precautions were taken.

The National Bureau of Investigation (NBI), which has custody over Ampatuan, created Task Force Ampatuan to secure him for Tuesday's arraignment to be held in Camp Crame.

The task force, headed by head agent Roland Argabioso, will implement heightened security because of the long travel to Quezon City, NBI Director Nestor Mantaring said.

On issues that the Ampatuans were given special treatment while inside detention centers, Deputy Spokesman Gary Olivar said in a radio interview Monday that possible sanctions await members of the police if proven guilty of the act.

Olivar said equal treatment should be accorded to all prisoners and no special treatment should be given to the Ampatuans regardless of their influence or wealth.

But while Andal Jr. and other members of his family are already in the custody of the government, authorities are still looking for several other suspects in the Maguindanao massacre who are believed to have been hiding in Davao Region.

Buluan Vice Mayor Ismael Mangudadatu earlier told the media that some 100 massacre suspects are hiding in Davao City and have firearms with them.

On Monday, Davao City Police Office (DCPO) Director Ramon Apolinario admitted it is possible that the suspects could be hiding not just in Davao City but in other parts of the region as well.

He said they already have photos of the massacre suspects. These will be distributed to the different police stations in the city, Apolinario said.

The November 23 massacre in Maguindanao province has been considered by many as the worst poll-related violence in the country. At least 57 civilians, including 30 journalists, were killed in the carnage, prompting the government to declare Martial Law in the province days after the massacre. The martial rule, however, was lifted by President Gloria Macapagal-Arroyo but Maguindanao is still under state of emergency, along with Sultan Kudarat and Cotabato City, as of this posting Monday. (MCM/BOT/ECV/JMR/With PNA/Sun.Star Davao/Sunnex)