Most likely the Moros.
Could be yes, could be no.
KnR - Kidnap and ransom is practiced around the more corrupt parts of the world. That the Church is a victim will spawn a lot of sympathy from Filipinos. The crime is the target of law and order. Filipinos will be motivated to stop the crime whether Moro or not. The action was criminal perpetuated by criminals. Whether the criminal(s) is/are Moro is yet to be discovered.
The hunt is on.