Mamangun vs. People

The justifying circumstance of fulfillment of duty under paragraph 5, Article 11 of the Revised Penal Code necessitates that (1) the accused acted in the performance of a duty and (2) the injury inflicted is the necessary consequence of the due performance of such duty; failure to prove the second requisite renders the justification incomplete, warranting only a privileged mitigating circumstance.

On July 31, 1992, residents of Brgy. Calvario, Meycauayan, Bulacan chased a robbery suspect who fled to the rooftop of Antonio Abacan's house. Petitioner Rufino Mamangun, a police officer, along with two other officers, responded to the scene and proceeded to the rooftop. There, petitioner fired a single shot at a man, later identified as Gener Contreras, hitting him in the left arm and ultimately causing his death. Contreras was not the robbery suspect but a resident who had joined the chase.

• The Incident: On July 31, 1992, a robbery-holdup was reported in Brgy. Calvario, prompting residents, including the victim Gener Contreras, to chase the suspect onto a rooftop. Petitioner Mamangun and two other officers were dispatched. Upon reaching the rooftop, petitioner shot Contreras once in the left arm; the bullet penetrated his lung and vertebral column, causing his death.
• Prosecution Version: Eyewitness Crisanto Ayson testified that he accompanied the officers to the well-lit rooftop. Ayson stated that Contreras pleaded, "Hindi ako, hindi ako," to which petitioner replied, "Anong hindi ako?" before shooting the unarmed Contreras.
• Defense Version: Petitioner and his fellow officers denied Ayson's presence. They claimed it was dark and that Contreras was crouching. After identifying themselves as police, Contreras allegedly stopped, turned, and raised a stainless steel pipe toward petitioner's head. Petitioner evaded the attack and shot Contreras in the left arm. Contreras then said, "Hindi ako."
• Medical and Physical Evidence: The autopsy revealed the bullet entered the outer upper left arm and exited near the left armpit. The Sandiganbayan found the bullet trajectory belied the claim that Contreras was facing and attacking petitioner, indicating instead that Contreras instinctively shielded his body. Furthermore, petitioner did not report the alleged pipe attack to the investigator immediately after the incident; the pipe only surfaced after an investigator visited the scene.

• Fulfillment of Duty: Petitioner argued that the shooting was justified under paragraph 5, Article 11 of the Revised Penal Code because he was repelling Contreras' unlawful attack while lawfully performing his duty as a police officer responding to a robbery.
• Witness Credibility: Petitioner maintained that prosecution eyewitness Ayson's testimony was incredible and riddled with inconsistencies regarding where the victim was shot, where he died, and Ayson's own movements after the incident.

• Incomplete Justification: Respondent countered that while petitioner was performing his duty, the shooting was not a necessary consequence thereof, warranting only an incomplete justifying circumstance.
• Absence of Unlawful Aggression: Respondent argued that self-defense was unavailable because Contreras did not commit unlawful aggression; he was unarmed and had identified himself as a non-suspect before being shot.
• Fabricated Defense: Respondent asserted that the claim of a steel pipe attack was an afterthought, not reported initially, and contradicted by the bullet trajectory and petitioner's post-shooting question to the victim.

• Fulfillment of Duty: Whether petitioner is exempt from criminal liability under the justifying circumstance of fulfillment of duty.
• Self-Defense: Whether self-defense, complete or incomplete, can be appreciated absent unlawful aggression from the victim.
• Witness Credibility: Whether the prosecution eyewitness's testimony should be disregarded due to alleged inconsistencies.

• Fulfillment of Duty: Exemption from criminal liability was denied. While the first requisite (acting in the performance of duty) was present, the second requisite (injury being the necessary consequence of duty) was absent. Shooting an unarmed civilian who had identified himself as a non-suspect was not a necessary consequence of apprehending a robber.
• Self-Defense: Self-defense, complete or incomplete, was rejected. Unlawful aggression, the most essential element of self-defense, was absent. The victim was unarmed, pleaded his innocence, and the bullet trajectory indicated he was shielding himself rather than attacking. The defense's claim of a pipe attack was deemed a concocted afterthought, as petitioner failed to report it immediately and the trajectory contradicted a face-to-face attack.
• Witness Credibility: The alleged inconsistencies in the prosecution witness's testimony pertained to minor details not touching upon the central fact of the crime. Such minor discrepancies even strengthen credibility by discounting the possibility of rehearsed testimony.

• Fulfillment of Duty (Art. 11, par. 5, RPC) — Requires (1) the accused acted in the performance of a duty, and (2) the injury inflicted or offense committed is the necessary consequence of the due performance of such duty. Applied to hold that while the first element was present, the second was lacking, as shooting an unarmed resident was not a necessary consequence of responding to a robbery.
• Unlawful Aggression — The most essential and primary element of self-defense; without it, self-defense must fail. Applied to reject self-defense because the victim was unarmed, had pleaded innocence, and the bullet trajectory indicated a defensive posture rather than an attack.
• Incomplete Justifying Circumstance — When only one requisite of a justifying circumstance is present, it operates as a privileged mitigating circumstance under Articles 13 and 69 of the Revised Penal Code. Applied to reduce the penalty for homicide, as only the first requisite of fulfillment of duty was established.

• "The justifying circumstance of fulfillment of duty under paragraph 5, Article II, of the Revised Penal Code may be invoked only after the defense successfully proves that: (1) the accused acted in the performance of a duty; and (2) the injury inflicted or offense committed is the necessary consequence of the due performance or lawful exercise of such duty."
• "Lacking this essential and primary element of unlawful aggression, petitioner’s plea of self-defense, complete or incomplete, must have to fail."

• Resoso v. Sandiganbayan, G.R. No. 124140 — Followed: Factual findings of the Sandiganbayan are conclusive upon the Supreme Court unless specific exceptions apply (e.g., findings grounded on speculation, grave abuse of discretion, misapprehension of facts).
• People v. Cawaling, G.R. No. 117970 — Followed: Requisites for the justifying circumstance of fulfillment of duty.
• People v. Givera, G.R. No. 132159 — Followed: Minor inconsistencies in a witness's testimony do not impair credibility and may even strengthen it by discounting rehearsal.

• Paragraph 5, Article 11, Revised Penal Code — Justifying circumstance of fulfillment of duty or lawful exercise of a right or office. Applied to determine if petitioner was exempt from liability; only the first element was present, resulting in incomplete justification.
• Articles 13 and 69, Revised Penal Code — Privileged mitigating circumstances and penalty rules for incomplete justifying circumstances. Applied to reduce the penalty for the homicide conviction.
• Article 249, Revised Penal Code — Defines and penalizes Homicide. Petitioner was convicted under this article.

Reynato S. Puno, Angelina Sandoval-Gutierrez, Renato C. Corona, Adolfo S. Azcuna