The Manila Police District conducted an operation in the Islamic Center on May 5, 3 a.m., a day before the twin explosion in Quiapo last Saturday.
Target of the saturation drive was alias Saro, an alleged bomb-maker responsible for making the improvised explosive device (IED) that detonated on April 28, 2017, also in Quiapo, during the height of the ASEAN Summit.
Authorities recovered a suspicious bag inside the stockroom of a house at the Islamic Center in Bgy 648. Zone 67, San Miguel, Manila.
The bag contained a disassembled pipe bomb IED component, GI pipe with arming switch, a wired mechanical timer, end caps of tubes, speaker parts, bolts and nuts to be used as shrapnel, empty shotgun shells, live ammunition and smokeless powder used as explosive filler.
According to the police Explosive and Ordinance Division (EOD), the parts are considered complete IED components, which can be assembled at any time.
The bomb components were similar to the IED that exploded in Quiapo on April 28.
Authorities are now investigating if the bombing incidents in Quiapo are related.
Sources said initial post-blast investigation revealed the presence of fragments of a tube pipe in area.
Bomb reconstruction is still ongoing to determine the kind of bomb used last Saturday.
"Yung EOD expert, sila ngayon yung magrereconstruct nung IED, 'yung improvised explosive device, and look on how it was triggered," said PNP spokesperson Senior Superintendent Dionardo Carlos in a press conference Tuesday.
Senior Superintendent Remigio Gregorio, chief of the EOD, said it is standard operating procedure for a bomb squad to check for secondary devices.
“Alam naman ng pulis ang SOP na kailangang i-check talaga 'yung area for secondary devices, nagkataon lang siguro na mabilis yung ibang unit na nakarating doon at di pa natatapos ang clearing operation ay nagkaroon na ng secondary explosion,” Gregorio said.
Meanwhile, international security analyst Dr. Rohan Gunaratna said it is possible that the explosions in Quiapo could be test runs conducted by local terrorists who have pledged allegiance to ISIS.
“We have not come across a case where they have falsely admitted an attack when they didn't do it. That's why it is so important for Philippine authorities, if they are saying this is not a terrorist attack, then they should immediately move forward and arrest those who are responsible.
"Government should increase intelligence capabilities to protect Luzon and the Visayas, and to increase their operational capabilities to fight more effectively in Mindanao,” he said.
Gunaratna also urged the government to intensify its intelligence-gathering capability to prevent future attacks.