Military and police operatives said they found some 21 skeletal remains of suspected victims of NPA summary killings dubbed "Operation Ajos."
Maj. Samuel Sagun, regional Army spokesman, said former NPA rebels, whose identities were withheld for security reasons, tipped off authorities on the alleged killing field in San Fernando.
Murder charges against top NPA officials in the area are being readied.
Military officials said the victims were executed by their comrades in the late 80s and the early 90s on suspicion that they were government spies.
One of the captured NPA rebels who pointed the shallow graves also said that the NPA is massively recruiting minors aged 12 to 16, even to the point of threatening to harm their families if they refuse.
PNP Deputy Director General Avelino Razon Jr., Task Force Usig chief, and Brig. Gen. Jose Barbieto, commander of the Armys Fourth Infantry (Diamond) Division, said they are documenting the latest discovery of human skeletons found by the 26th Infantry Battalion (26th IB) in San Fernando.
Razon said they have already filed 13 cases against suspected NPA guerrillas involved in the killings.
Barbieto said initial findings of crime experts showed that the victims were tortured before they were killed.