Republic of the Philippines


G.R. No. 149152             February 2, 2007




In this petition for review under Rule 45 of the Rules of Court, petitioner Rufino Mamangun y Silverio seeks the reversal of the Decision1 dated January 19, 2001 (promulgated on February 13, 2001) of the Sandiganbayan in its Criminal Case No. 21131, convicting him of the crime of Homicide.

The factual backdrop:

On September 12, 1994, herein petitioner, then a police officer, was charged before the Sandiganbayan with the crime of Murder, allegedly committed, per the indicting Information,2 docketed as Criminal Case No. 21131, as follows:

That on or about the 31st day of July 1992, in the Municipality of Meycauyan, (sic) Province of Bulacan, Philippines, and within the jurisdiction of this Honorable Court, the said accused Rufino S. Mamangun, a public officer, being then a Police Officer (PO2), duly appointed as such and acting in relation to his office, armed with a gun, with intent to kill, did then and there willfully, unlawfully and feloniously, with treachery, evident premeditation and abuse of superior strength, attack, assault and shoot one Gener M. Contreras with the said gun, hitting the latter on his body, thereby inflicting (sic) him serious physical injuries which directly cause (sic) his death.


On arraignment, petitioner, as accused below, duly assisted by a counsel de oficio, entered a plea of "Not Guilty."

In the ensuing trial, the prosecution presented in evidence the testimonies of Crisanto Ayson (Ayson), an alleged eyewitness, and Dr. Benito Caballero, then the designated Medico-Legal Officer of Bulacan who performed an autopsy on the cadaver of the victim.

For its part, the defense adduced in evidence the testimonies of the accused himself, Rufino Mamangun, his co-policemen at the Philippine National Police (PNP), namely, PO2 Carlito Cruz, PO4 Hobert O. Diaz and Police Investigator SPO-1 Hernando B. Banez, all assigned at the Meycauayan Police Station; and those of Lorenzo S. Abacan and Rogelio Ingco, son and son-in-law, respectively, of Antonio Abacan, owner of the house on which rooftop the shooting of the victim took place.

It is not disputed that on July 31, 1992, at about 8:00 in the evening, in Brgy. Calvario, Meycauayan, Bulacan a certain Liberty Contreras was heard shouting, "MagnanakawÖMagnanakaw." Several residents responded and thereupon chased the suspect who entered the yard of Antonio Abacan and proceeded to the rooftop of Abacanís house.

At about 9:00 oíclock that same evening, the desk officer of the Meycauayan PNP Police Station, upon receiving a telephone call that a robbery-holdup was in progress in Brgy. Calvario, immediately contacted and dispatched to the scene the crew of Patrol Car No. 601 composed of Team Leader SPO1 Andres Legaspi, with PO2 Eugenio Aminas and herein petitioner PO2 Rufino S. Mamangun; and Patrol Car No. 602 composed of Team Leader PO3 Sandiego San Gabriel, with PO2 Carlito Cruz and PO2 Hobert Diaz. With the permission of Abacan, petitioner Mamangun, PO2 Diaz and PO2 Cruz went to the rooftop of the house whereat the suspect was allegedly taking refuge.

The three policemen, i.e., petitioner, Diaz and Cruz, each armed with a drawn handgun, searched the rooftop. There, they saw a man whom they thought was the robbery suspect. At that instance, petitioner Mamangun, who was walking ahead of the group, fired his handgun once, hitting the man. The man turned out to be Gener Contreras (Contreras) who was not the robbery suspect.

Contreras died from the gunshot wound. The autopsy conducted by Dr. Benito B. Caballero yielded the following findings:

The cause of death was "Shock due to massive external and internal hemorrhage due to multiple gunshot wounds in the left arm side of the thorax, penetrating the left lung and vertebral column." There were several wounds caused by one (1) bullet.

As shown on the sketch of human body attached to the Certificate of Death, and as testified on by Dr. Caballero, the bullet entered through the "lower third of the left arm, left side of the thorax and it penetrated the left lung and vertebral column and that is where the slug was found." From a laymanís appreciation of the sketch, the bullet entered the outer, upper left arm of the victim, exited through the inner side of the said upper left arm, a little lower than the left armpit and the slug lodging on the victimís back where it was recovered at the vertebral column.3

From the foregoing admitted or undisputed facts, the prosecution and the defense presented conflicting versions as to how the fatal shooting of Contreras by petitioner Mamangun actually happened.

According to Ayson, the lone eyewitness for the prosecution, he accompanied the three policemen (Mamangun, Diaz and Cruz) to the rooftop of Abacanís house. He was following petitioner Mamangun who was ahead of the group. They passed through the second-floor door of the house to the rooftop. The roof was lighted by an incandescent bulb from an adjacent house. He was beside Mamangun when they saw, some four to five arms-length away, a man whom he (witness) recognized as Gener Contreras. Mamangun pointed his .45 cal. pistol at the man, who instantly exclaimed, "Hindi ako, hindi ako!," to which Mamangun replied, "Anong hindi ako?" Before he (Ayson) could say anything, Mamangun fired his gun, hitting the man who turned out to be Contreras. He (witness) approached the victim who was then lying on his left side unconscious. He brought down the victim and they rushed him to the hospital where he died at about 10:00 oíclock that same evening.

The defense has its own account of what purportedly actually

PO2 Mamangun, along with PO2 Cruz and PO2Diaz, denied the presence of Ayson at the rooftop during the shooting incident. Corroborating one another, the three testified that they were the only ones at the scene of the shooting, and that it was dark. They claimed that each of them, with Mamangun on the lead, went on separate directions around a water tank. As they met each other at the other side of the tank, PO2 Cruz pointed to a person crouching at the edge of the roof of the garage. Thinking that the person was the suspect they were looking for, Mamangun chased said person. They announced that they were police officers but the person continued to run in a crouching position until Mamangun caught up with him and shouted, "Pulis. Tigil," whereupon the person suddenly stopped, turned around, faced Mamangun, and raised a stainless steel pipe towards the latterís head but Mamangun was able to evade the attack. This prompted Mamangun to shoot the person on the left arm. All three claimed that it was only at this point that PO2 Cruz and Diaz approached Contreras who told them, "Hindi ako. Hindi ako." Mamangun went near Contreras and asked, "Why did you go to the rooftop? You know there are policemen here." Contreras was thereafter brought to the hospital where he died. After the shooting incident, Mamangun reported the same to the desk officer, POI Filomeno de Luna, who advised him to remain in the police station. De Luna directed Police Investigator Hernando Banez to investigate the incident. That same evening, Investigator Banez went to the place where the shooting happened. Banez allegedly found a steel pipe about three (3) feet long on the depressed portion of the roof.

On January 19, 2001, after due proceedings, the Sandiganbayan came out with its decision4 finding the petitioner guilty beyond reasonable doubt of only the crime of Homicide. In so finding, the Sandiganbayan did not appreciate the presence of the aggravating circumstances of treachery, evident premeditation and abuse of superior strength to qualify the killing to Murder. But even as the said court rejected the petitionerís claim that the shooting was justified by self-defense, it nonetheless ruled that the crime of Homicide was attended by an incomplete justifying circumstance of the petitioner having acted in the performance of his duty as a policeman, and also appreciated in his favor the generic mitigating circumstance of voluntary surrender. Dispositively, the decision reads:

WHEREFORE, the accused, RUFINO S. MAMANGUN, is hereby found GUILTY beyond reasonable doubt of the crime of Homicide, defined and penalized under Article 249, Revised Penal Code, and taking into account the attendance of one (1) privileged mitigation (sic) circumstance, one generic circumstance and no aggravating circumstance, he is hereby sentenced under the Indeterminate Sentence Law, to suffer the penalty of imprisonment of from Three (3) Years and Three (3) Months of prision correctional as minimum, to Seven (7) years of prision mayor, as maximum, to indemnify the heirs (parents) of Gener Contreras in the total amount of P352,025.00, and to past the costs.


Unable to accept the judgment of conviction, petitioner is now with this Court via the present recourse alleging that the Sandiganbayan committed reversible error in failing to apply paragraph 5, Article 11, of the Revised Penal Code, which would have absolved him from criminal liability on the basis of his submission that the shooting in question was done in the performance of a duty or in the lawful exercise of a right or office.

First off, petitioner insists that the shooting, which ultimately caused the demise of Contreras, was justified because he was repelling Contrerasí unlawful attack on his person, as Contreras was then about to strike him on the head with a steel pipe.

We are not persuaded.

Well-settled is the rule that factual findings of the Sandiganbayan are conclusive upon the Court except where: (1) the conclusion is a finding grounded entirely on speculations, surmises and conjectures; (2) the inference made is manifestly mistaken; (3) there is grave abuse of discretion; (4) the judgment is based on misapprehension of facts and the findings of fact are premised on the absence of evidence and are contradicted by the evidence on record.5 None of these exceptions obtains in this case.

Having admitted6 the fatal shooting of Contreras on the night of July 31, 1992, petitioner is charged with the burden of adducing convincing evidence to show that the killing was done in the fulfillment of his duty as a policeman.

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.7

Concededly, the first requisite is present in this case. Petitioner, a police officer, was responding to a robbery-holdup incident. His presence at the situs of the crime was in accordance with the performance of his duty. However, proof that the shooting and ultimate death of Contreras was a necessary consequence of the due performance of his duty as a policeman is essential to exempt him from criminal liability.

As we see it, petitionerís posturing that he shot Contreras because the latter tried to strike him with a steel pipe was a mere afterthought to exempt him from criminal liability.

We see no plausible basis to depart from the Sandiganbayanís findings that there was no reason for the petitioner to shoot Contreras. The latter was unarmed and had already uttered, "Hindi po ako, Hindi po ako" before the petitioner fatally shot him on the left arm. Prosecution witness Ayson, who was then behind the petitioner when the latter shot Contreras, testified that to the victimís utterances, the petitioner even responded, "Anong hindi ako," and immediately shot Contreras.8 As correctly observed by the Sandiganbayan:

Besides being self-serving (with respect to the accused) and biased (with respect to his co-policemen-witnesses), We find (1) the claim of the accused and his co-policemen-witnesses that the victim (Contreras) attacked the said accused and (2) their seemingly "positive" identification of the stainless steel pipe (more of a rod) as his weapon, to be of doubtful credibility, for the following reasons:

(1) We have no doubt that, as claimed by PO2 Carlito Cruz and PO2 Hobert Diaz, the three policemen appropriately identified themselves as police officers as they started chasing the man they saw "crouching," and, as claimed by accused PO2 Rufino Mamangun, that, as he was about to catch up with said man, he shouted, "Pulis! Tigil!" With all these introductions and forewarnings, it is utterly incredible and contrary to human experience that, that man, later identified to be Gener Contreras and admittedly not the person they were looking for, purportedly armed only with a stainless steel "lead" pipe (more of a rod) would suddenly stop, turn around and attack one of the three policemen who were chasing him, one after the other, with drawn guns.

(2) When the victim (Gener Contreras) fell down after being shot by accused PO2 Mamangun, and as the latter went near the fallen victim, said accused asked, "Why did you go to the rooftop. You know there are policemen here." He admits that he did not ask the victim, "Why did you try to hit me, if you are not the one?" This admission clearly belies the claim of the police-witnesses that Gener Contreras attacked the accused policeman with an iron pipe when he was shot, for the accused should have asked the latter question.

(3) The location of the entry of the bullet fired by accused Mamangun which is at the outer left arm at about the bicep of the victim and its trajectory as it penetrated his body hitting his vital organs along the way belies the claim of the accused that the victim was facing him and had just missed his head with an iron pipe, as instead the victim must have instinctively shielded his body with his left arm.

Moreover, petitionerís pretense that Contreras struck him with a steel pipe is intriguing. As it is, petitioner did not report the same to Police Investigator Banez when he reported back to the police station after the shooting incident. It was only when a lead pipe was recovered from the scene and brought to the police station that petitioner conveniently remembered Contreras trying to hit him with a pipe. Such a vital information could not have escaped the petitionerís mind. We are thus inclined to believe that the alleged actuation of Contreras, which could have justified petitionerís shooting him, was nothing but a concocted story to evade criminal liability. Indeed, knowing that he shot Contreras, the least that the petitioner should have done was to bring with him to the police station the very pipe with which Contreras tried to attack him. As borne by the evidence, however, it was only after a police investigator referred to the scene that the lead pipe surfaced.

Petitioner would likewise argue that the testimony of prosecution witness Ayson was incredible and riddled with inconsistencies.

The alleged contradictions cited by the petitioner, i.e. where the victim was shot, where he died, and as to whether Ayson left his house after the shooting incident, are but minor details which do not affect Aysonís credibility. We have held time and again that few discrepancies and inconsistencies in the testimony of a witness referring to minor details and not in actuality touching upon the central fact of the crime, do not impair his credibility. Quite the contrary, such minor inconsistencies even tend to strengthen credibility because they discount the possibility that the testimony was rehearsed.9

For sure, the record reveals that Aysonís answers to the questions propounded by the defense counsel are clear and categorical. As to where the victim died, Ayson clarified that the victim was already at the rooftop even before the arrival of the police officers. As to why he was not able to warn Mamangun that the victim was his relative, Ayson explained that he was not able to utter any word because when Contreras said "Hindi ako. Hindi ako," petitioner suddenly fired at the latter.10 As to the claim that Ayson was also on the roof, record shows that the robbery-holdup happened at around 8:00 in the evening. Before the policemen arrived, Ayson and Contreras were already pursuing the robber.11 Ayson also testified that when the victim was shot by the petitioner, the former fell on his left side unconscious; that he did not leave his house after the incident because he was afraid that the policemen would detain him.12

Self-defense, whether complete or incomplete, cannot be appreciated as a valid justifying circumstance in this case. For, from the above admitted, uncontroverted or established facts, the most important element of unlawful aggression on the part of the victim to justify a claim of self defense was absent. Lacking this essential and primary element of unlawful aggression, petitionerís plea of self-defense, complete or incomplete, must have to fail.

To be sure, acts in the fulfillment of a duty, without more, do not completely justify the petitionerís firing the fatal gunshot at the victim. True, petitioner, as one of the policemen responding to a reported robbery then in progress, was performing his duty as a police officer as well as when he was trying to effect the arrest of the suspected robber and in the process, fatally shoot said suspect, albeit the wrong man. However, in the absence of the equally necessary justifying circumstance that the injury or offense committed be the necessary consequence of the due performance of such duty, there can only be incomplete justification, a privileged mitigating circumstance under Articles 13 and 69 of the Revised Penal Code.

There can be no quibbling that there was no rational necessity for the killing of Contreras. Petitioner could have first fired a warning shot before pulling the trigger against Contreras who was one of the residents chasing the suspected robber.

All told, we find no reversible error committed by the Sandiganbayan in convicting the petitioner of the crime of Homicide attended by the privileged mitigating circumstance of incomplete justifying circumstance of having acted in the performance of his duty as a policeman and the generic mitigating circumstance of voluntary surrender.

IN VIEW WHEREOF, the instant petition is DENIED and the assailed decision of the Sandiganbayan is AFFIRMED in all respects.

No pronouncement as to costs.


Associate Justice


Chief Justice

Associate Justice
Asscociate Justice

Associate Justice


Pursuant to Section 13, Article VIII of the Constitution, I certify that the conclusions in the above decision had been reached in consultation before the case was assigned to the writer of the opinion of the Courtís Division.

Chief Justice


1 Penned by Associate Justice Nicodemo T. Ferrer with Associate Justices Narciso S. Nario and Rodolfo G. Palatao, concurring; Rollo, pp. 25-46.

2 Sandiganbayan Record, Vol. I, p. 1.

3 As culled from the Sandiganbayan decision, Id. at 29.

4 Supra note 1.

5 Resoso v. Sandiganbayan, G.R. No. 124140, November 25, 1999, 319 SCRA 238, 244.

6 TSN, p. 11; Hearing on May 27, 1996.

7 People v. Cawaling, G.R. No. 117970, July 28, 1998, 293 SCRA 267.

8 TSN, pp. 22, 29. Hearing on March 23, 1995.

9 People v. Givera, G.R. No. 132159, January 18, 2001, 349 SCRA 513, 530.

10 TSN, pp. 9-10, March 23, 1996.

11 Ibid at p. 20.

12 Ibid at p. 15.

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