MANILA, Philippines – Government bomb experts are focusing on a group who could be behind the bombing of the passenger bus in Makati City last Jan. 25, after forensic examination of the wreckage showed traces of explosive residue known as pentaerythritol tetranite or PETN.
Police and military investigators are digging into their files of bombings all over the country to determine which terrorist group had used PETN in past bombings. PETN, which is hard to detect, has been used in attempts to bomb airlines in other countries.
PETN is a white crystalline solid with a melting point of 141 degrees Celsius and found mainly in detonating cords. “It is a stable explosive if kept free from acid, but becomes more sensitive with the presence of grit or dust,” the source said. PETN is often used as a booster charge for the main explosive device.
A member of the Task Force Goldliner confirmed to The STAR that traces of PETN were found in the bus after the bombing that left five people dead and 13 others injured.
“We have some positive developments in our investigation in the bus bombing but I cannot disclose these at this time for fear of jeopardizing ongoing operations,” said a Task Force Goldliner member, noting that they are now in the intelligence aspect of their investigation.
Aside from PETN, forensic experts also found traces of TNT, he said.
Police and military investigators narrowed down to three Muslim extremist groups – the Abu Sayyaf, Rajah Solaiman Movement and Special Operations Group of the Moro Islamic Liberation Front (MILF) – the probable suspects in the bus bombing.
Because of the sensitivity of the issue, the Task Force Goldliner members refused to say who among the three Muslim extremist groups are using PETN in their bombing operations.
“We are checking our records and files of bombings in the past, particularly in Mindanao, to get the signature of the group behind the bomb blast in Makati City,” he added.
The government offered a P3-million reward for information leading to the suspects in the bombing. A police artist also prepared sketches of two persons who could have planted the bomb on the sixth row of the bus. As of yesterday, nobody has come forward to offer solid information on the bombers.