Related Rule
Practice Relating to Rule 89. Violence to Life
The Rules for Combatants (1989) of the Philippines provides: “Prisoners must be respected. It is prohibited to … kill them.” 
Philippines, Rules for Combatants, in Handbook on Discipline, Annex C(II), General Headquarters, Armed Forces of the Philippines, Camp General Emilio Aguinaldo, Quezon City, 1989, § 6(4).
The Philippine National Police (PNP) Manual on Ethical Doctrine (1995) provides:
Respect for Human Rights – In the performance of duty, PNP members shall respect and protect human dignity and uphold the human rights of all persons. No member shall inflict, instigate or tolerate extrajudicial killings, arbitrary arrests, any act of torture or other cruel, inhuman or degrading treatment or punishment, and shall not invoke superior orders or exceptional circumstances such as a state-of-war, a threat to national security, internal political instability or any public emergency as a justification for committing such human rights violations. 
Philippines, Manual on Ethical Doctrine, PNPM-0-0-8-95 (DHRDD), Directorate for Human Resource and Doctrine Development, National Headquarters, Philippine National Police, Revised, August 1995 Edition, Section 2.9.
The Philippine Army Soldier’s Handbook on Human Rights and International Humanitarian Law (2006) provides:
During an engagement:
4. Don’t kill enemy combatants who are wounded, who could no longer fight or who have already surrendered. By International Humanitarian Law, it is authorized to neutralize enemy forces by reasonable means while in combat. An enemy who wields a firearm and considered a threat is still a military objective and thus considered an authorized target. As long as he is wielding his firearm, he can still be considered as target for neutralization. But as soon as he drops his firearm, raises his hand or a white cloth that is a gesture of symbol of surrender, he can no longer be shot. 
Philippines, Philippine Army Soldier’s Handbook on Human Rights and International Humanitarian Law, A Practical Guide for Internal Security Operations, 2006, p. 59, § 4.
Under the War Crimes Trial Executive Order (1947) of the Philippines applicable to acts committed during the Second World War, “murder of civilian population of or in occupied territory; murder … of prisoners of war or internees or persons on the seas or elsewhere” are violations of the laws and customs of war. 
Philippines, War Crimes Trial Executive Order, 1947, Part II(b)(2).
The Executive Order adds that “murder, extermination [of] … civilian populations before or during [the Second World War]” constitute war crimes whether or not in violation of the local laws. 
Philippines, War Crimes Trial Executive Order, 1947, Part II(b)(3).
The Philippines’ Executive Order No. 8 (1986), creating the Presidential Committee on Human Rights, states that the Committee shall have the following functions:
Investigate complaints it may receive, cases known to it or to its members and such cases as the President may, from time to time assign to it, of unexplained or forced disappearances, extra-judicial killings (salvaging), massacres, torture … and other violations of human rights, past or present, committed by officers or agents of the national government or persons acting in their place or stead or under their orders, express or implied. 
Philippines, Executive Order No. 8, 1986, Section 4a.
The Philippines’ Republic Act No. 8438 (1997) provides: “The regional government [of the Cordillera Autonomous Region] shall take measures to prevent torture; other cruel, inhuman, and degrading treatment or punishment; and illegal detention and extra-judicial executions.” 
Philippines, Republic Act No. 8438, 1997, Section 27.