This developed as Muntinlupa police investigators zeroed in on the "vendetta angle," probably against the cops, owing to the recent series of police crackdowns in the area against illegal vendors, colorum jeepneys, and snatchers.
Killed in the blast were seven-month-old Michaela and her four-year-old sister Dianne Beronia. Their mother, who remained unidentified as of press time, was also injured. Her present whereabouts could not be ascertained.
Also injured were Senior Police Officer 2 Rodelio Pulhin and PO3 Ronnie Seles. The two cops were then patrolling the busy Montillano street corner Alabang viaduct when the blast occurred at about 8:30 p.m.
Investigator on case SPO2 Ed Orongan said the other wounded victims are now in stable condition.
"We are not saying that (Moro rebels) or NPAs (communist New People’s Army) are behind it but we are looking at all angles," said Southern Police District (SPD) director Chief Superintendent Jose Guttierez Jr.
Guttierez also dismissed reports that the incident could be part of any destabilization efforts against the Arroyo administration.
The NPA angle cropped up after witnesses said the grenade-throwers, numbering from three to four, allegedly shouted that they are members of the NPA.
Guttierez said the attackers may be trying to mislead investigators when they claimed they were communists rebels.
On the other hand, the Muntinlupa City police, particularly members of the traffic division, had been allegedly receiving threats that "they will be blown away" due to their campaign against illegal vendors, most of whom are Mindanao natives.
The 30 police reinforcement are expected to be deployed in the same busy area.
The SPD chief said probers are seriously looking into the vendetta angle but would not explicitly say whether the attack was directed at the policemen or any other officials.
"If they (the grenade-throwers) were really targetting a particular person, they could have simply approached them (cops) and shot them in the head," said Guttierez.
The SPD chief said the attackers could also have simply lobbed the grenade with no particular target in mind.
Cartographic sketches of the grenade-throwers, said to be in their early 20s, are now being prepared by police. Police officials claimed they have leads on the attackers and could make arrests soon.