Police detained three men, including the victims son-in-law who was implicated by the two other suspects in the grisly killings.
Generoso Casupong, 65, and his wife Isabelita, 64, were both decapitated inside their home in Barangay Bulata by two men armed with a large curved knife used to harvest coconut, said Cauayan police investigator Alvin Cuenca.
Detained suspect Eugenio Tanguar, 43, blamed the couple for the death of his daughter from an unspecified illness last year.
Speaking to reporters behind his jail cell, Tanguar said he threw the womans severed head in the hearth in the belief that the ashes would prevent the alleged witch from reattaching her body and coming back to life.
Radio reports quoted him as saying that he dipped the womans head in apog (lime) to prevent it from reattaching to the body.
Another suspect, Carlito Hibolan, 28, said he used the same knife to kill the husband.
"He was shouting for help and I was in a hurry to kill him because I know aswang (witches) are strong and I was afraid he might overpower me," Hibolan said.
The two claimed the third suspect, Rosendo Cabug-os, had encouraged them to kill his in-laws, also believing them to be witches.
Cabug-os denied any role in the attacks. All three suspects were arrested on Tuesday. AFP, Antonieta Lopez