This is a petition for review of the Decision^[1] of the Court of Appeals (CA) in CA-G.R. CR No. 23742 affirming on appeal, the Decision^[2] of the Regional Trial Court (RTC) of Odiongan, Romblon, Branch 82, in Criminal Case No. OD-861, convicting the petitioner of homicide.

In an Information filed in the RTC of Romblon, the petitioner was charged with homicide allegedly committed as follows:

That on or about the 16th day of September 1995, at around 9:30 o'clock in the evening, in Barangay Libertad, municipality of Odiongan, province of Romblon, Philippines, and within the jurisdiction of this Honorable Court, the said accused, with intent to kill, did then and there, willfully, unlawfully and feloniously attack, assault and stab with a bolo, one RICKY F. GUARTE, which causes (sic) his untimely death.

Contrary to law.^[3]

In due course, the prosecution adduced evidence against the petitioner which was synthesized by the appellate court as follows:

On September 16, 1995, appellant went to a black-smith who made the design of his bolo.  When he went home to Tuburan, Odiongan, Romblon late in the afternoon (TSN, September 4, 1998, p. 2), appellant saw the group of Lani Famero, Michael Fosana, Rex Cortez and Ricky Guarte drinking gin at the house of the Spouses Manuel and Eliza Guarte, Ricky's parents.  Appellant's house is about five (5) meters away from the house of Spouses Guarte.  Appellant requested the group of Ricky to refrain from making any noise.  Thereupon, appellant proceeded inside his house and went to sleep (ibid., p. 3).  Around 9:00 p.m., Gerardo Faminia, Eliza Guarte's brother arrived at the Guarte house and asked for any left-over food (TSN, August 5, 1998, p. 3).  Eliza prepared dinner for him and after Gerardo finished eating, he went home accompanied by Ricky (TSN, April 26, 1996, p. 5).  Gerardo's home is about twelve (12) meters away from the Guarte home (TSN, February 17, 1997, p. 11).  Minutes later, Ricky came back and together with Lani, Rex and Michael, went to sleep at the Guarte house.  They had not laid down for long when they heard stones being hurled at the roof of the house.  The stoning was made three (3) times (TSN, August 5, 1998, pp. 2-3).  Ricky rose from bed and peeped through a window.  He    saw appellant stoning their house.  Ricky went out of the house and proceeded to appellant's house.  Ricky asked appellant, his uncle, why he was    stoning their house.  Appellant did not answer but met Ricky at the doorstep of his (appellant's) house (TSN, April 26, 1996, p. 6; August 5, 1998, pp. 4-5) and, without any warning, stabbed Ricky on the abdomen with a bolo (TSN, August 5, 1998, p. 8).  Eliza had followed his son Ricky and upon seeing that Ricky was stabbed, shouted for help (TSN, February 17, 1997, p. 13).  Lani heard Eliza's cry for help and immediately rushed outside the house.  Lani saw Ricky leaning on the ground and supporting his body with his hands.  Lani helped Ricky stand up and brought him to the main road.  Lani asked Ricky who stabbed him and Ricky replied that it was appellant who stabbed him.  Then Docloy Cortez arrived at the scene on board his tricycle.  Accordingly, Ricky was put on the tricycle and taken to the Romblon Provincial Hospital (TSN, January 19, 1998, pp. 4-6).

At the Romblon Provincial Hospital, Dr. Noralie Fetalvero operated on Ricky that very night.  Ricky had sustained one (1) stab wound but due to massive blood loss, he died while being operated on (TSN, November 24, 1997, pp. 2, 6-7).  Dr. Fetalvero issued a Medico-Legal Certificate showing the injuries sustained by Ricky, thus:

Stab wound, left chest with gastric & transverse colon evisceration measuring 6 cms. long, irregular-edged at 8^th ICS, left penetrating (operative findings):

(1) abdominal cavity perforating the stomach (thru & thru) and the left lobe of the liver

(2) thoracic cavity thru the left dome of the diaphragm perforating the lower lobe of the left    lung.

…

(Exhibit C)

The Certificate of Death issued by Dr. Fetalvero stated the cause of Ricky's death as:

CAUSES OF DEATH:
Immediate cause  :			a.  Cardiorespiratory Arrest
Antecedent cause :			b.  Hypovolemic shock
Underlying cause :			c.  Multiple thoraco-abdominal
	injury 2º to stab wound

(Exhibit B)^[4]

The petitioner adduced evidence that at around 5:00 p.m. on September 16, 1995, he was on his way home at Tuburan, Odiongan, Romblon.  He saw his nephew, Ricky Guarte, and the latter's friends, Michael Fosana, Rex Cortez, and Lani Famero, about five meters away from his house, having a drinking spree.  He ordered them not to make loud noises, and they obliged.  He then went to his house, locked the door with a nail, and went to sleep.  However, he was awakened at around 9:30 p.m. by loud noises coming from Ricky and his three companions.  He peeped through the window grills of his house and admonished them not to make any loud noises.  Ricky, who was then already inebriated, was incensed; he pulled out a balisong, pushed the door, and threatened to stab the petitioner.  The petitioner pushed their sala set against the door to block the entry of Ricky, but the latter continued to push the door open with his hands and body.  The petitioner ran to the upper portion of their house and got his bolo.^[5] He returned to the door and pushed it with all his might using his left hand.  He then pointed his bolo, which was in his right hand, towards Ricky.  The bolo accidentally hit Ricky on the stomach, and the latter lost his balance and fell to the floor.  The petitioner, thereafter, surrendered to the barangay captain at 11:00 a.m. on September 17, 1995.

After trial, the court rendered judgment finding the petitioner guilty as charged.  The fallo of the decision reads:

WHEREFORE, premises considered, NOE TOLEDO is hereby found GUILTY beyond reasonable doubt of homicide with the mitigating circumstance of voluntary surrender and is meted the indeterminate penalty of from six (6) years and one (1) day of prision mayor minimum, as minimum, to twelve (12) years and one (1) day of reclusion temporal minimum, as maximum.

Accused is condemned to pay the amount of P50,000.00 as civil liability to the heirs of the victim.^[6]

The trial court did not give credence and probative weight to the testimony of the petitioner that his bolo accidentally hit the victim on the    stomach.

On appeal in the CA, the petitioner raised the following issue in his brief as appellant:

WHETHER OR NOT ACCUSED-APPELLANT CAN BE CRIMINALLY HELD LIABLE FOR THE ACCIDENTAL DEATH OF RICKY GUARTE^[7]

Invoking Article 12, paragraph 4 of the Revised Penal Code, the petitioner claimed that he stabbed the victim by accident; hence, he is exempt from criminal liability for the death of the victim.

The CA rendered judgment affirming the assailed decision with modifications.  The CA also denied the    petitioner's motion for reconsideration thereof.  The appellate court ruled that the petitioner failed to prove that he acted in self-defense.

Aggrieved, the petitioner filed the instant petition for review, contending that the CA erred in not finding that he acted in self-defense when he stabbed the victim by accident and prays that he be acquitted of the crime    charged.

The sole issue in this case is whether or not the petitioner is guilty beyond reasonable doubt of homicide based on the evidence on record.

The petitioner contends that the CA committed a reversible error when it affirmed the decision of the RTC convicting him of homicide, on its finding that he failed to prove that he acted in complete self-defense when the victim was hit by his bolo.  The petitioner insists that he acted in complete self-defense when his bolo accidentally hit the victim on the stomach.

For its part, the Office of the Solicitor General asserts that the petitioner failed to prove self-defense with clear and convincing evidence.  Hence, the decision of the CA affirming, on appeal, the decision of the RTC is correct.

The contention of the petitioner has no merit.

The petitioner testified that his bolo hit the victim accidentally.  He asserted in the RTC and in the CA that he is exempt from criminal liability for the death of the victim under Article 12, paragraph 4 of the Revised Penal Code which reads:

4.       Any person who, while performing a lawful act with due care, causes an injury by mere accident without fault or intention of causing it.

In his brief in the CA, the petitioner argued that:

In the case at bar, with all due respect, contrary to the findings of the lower court, it is our humble submission that the death of Ricky Guarte was merely a sad and unwanted result of an accident without fault or intention of causing it on the part of accused-appellant.  We submit, there were clear and indubitable factual indicators overlooked by the lower court, bolstering the theory of the defense on accidental death.^[8]

However, the petitioner changed gear, so to speak, and now alleges that he acted in self-defense when he stabbed the victim.  As such, he contends, he is not criminally liable under Article 11, paragraph 1 of the Revised Penal Code which reads:

Art. 11.  Justifying circumstances. The following do not incur any criminal liability:

1. Anyone who acts in defense of his person or rights, provided that the following circumstances concur:

First.  Unlawful aggression;

Second.  Reasonable necessity of the means employed to prevent or repel it:

Third.  Lack of sufficient provocation on the part of the person defending himself.

The petitioner avers that he was able to prove the essential elements of complete self-defense, thus:

A close scrutiny of the records of the case would show that the petitioner acted in self-defense.

The essential requisites of self-defense are: (1) unlawful aggression on the part of the victim; (2) reasonable scrutiny of the means employed to prevent or repel it; and (3) lack of sufficient provocation on the part of the person defending himself (People vs. Silvano, 350 SCRA 650)^[9]

However, the petitioner also claims that his bolo accidentally hit the stomach of the victim.

It is a matter of law that when a party adopts a particular theory and the case is tried and decided upon that theory in the court below, he will not be permitted to change his theory on appeal.  The case will be reviewed and decided on that theory and not approached and resolved from a different point of view.  To permit a party to change his theory on    appeal will be unfair to the adverse party.^[10]

The petitioner is proscribed from changing in this Court, his theory of defense which he adopted in the trial court and foisted in the CA by claiming that he stabbed and killed the victim in complete self-defense.  The petitioner relied on Article 12, paragraph 4 of the Revised Penal Code in the trial and appellate    courts, but adopted in this Court two divergent theories (1) that he killed the victim to defend himself against his unlawful aggression; hence, is justified under Article 11, paragraph 1 of the Revised Penal Code; (2) that his bolo accidentally hit the victim and is, thus, exempt from criminal liability under Article 12, paragraph 4 of the Revised Penal Code.

It is an aberration for the petitioner to invoke the two defenses at the same time because the said defenses are intrinsically antithetical.^[11] There is no such defense as accidental self-defense in the realm of criminal law.

Self-defense under Article 11, paragraph 1 of the Revised Penal Code necessarily implies a deliberate and positive overt act of the accused to prevent or repel an unlawful aggression of another with the use of reasonable means.  The accused has freedom of action.  He is aware of the consequences of his deliberate acts.  The defense is based on necessity which is the supreme and irresistible master of men of all human affairs, and of the law.  From    necessity, and limited by it, proceeds the right of self-defense.  The right begins when necessity does, and ends where it ends.^[12] Although the accused, in fact, injures or kills the victim, however, his act is in accordance with law so much so that the accused is deemed not to have transgressed the law and is free from both criminal and civil liabilities.^[13] On the other hand, the basis of exempting circumstances under Article 12 of the Revised Penal Code is the complete absence of intelligence, freedom of action, or intent, or the absence of negligence on the part of the accused.^[14] The basis of the exemption in Article 12, paragraph 4 of the Revised Penal Code is lack of negligence and intent.  The accused does not commit either an intentional or culpable felony.  The accused commits a crime but there is no criminal liability because of the complete absence of any of the conditions which constitute free will or voluntariness of the act.^[15] An accident is a fortuitous circumstance, event or happening; an event happening wholly or partly through human agency, an event which under the circumstances is unusual or unexpected by the person to whom it happens.^[16]

Self-defense, under Article 11, paragraph 1, and accident, under Article 12, paragraph 4 of the Revised Penal Code, are affirmative defenses which the accused is burdened to prove, with clear and convincing evidence.  Such affirmative defenses involve questions of facts adduced to the trial and appellate courts for resolution.  By admitting killing the victim in self-defense or by accident without fault or without intention of causing it, the burden is shifted to the accused to prove such affirmative defenses.  He should rely on the strength of his own evidence and not on the weakness of that of the prosecution.  If the accused fails to prove his affirmative defense, he can no longer be acquitted.

The petitioner failed to prove that the victim was killed by accident, without fault or intention on his part to cause it.  The petitioner was burdened to prove with clear and convincing evidence, the essential requisites for the exempting circumstance under Article 12, paragraph 4, viz:

1.  A person is performing a lawful act;
2.  With due care;
3.  He causes an injury to another by mere accident;
4.  Without fault or intention of causing it.

To prove his affirmative defense, the petitioner relied solely on his testimony, thus:

Q	What happened next when Ricky Guarte was able to push through the door and you ran away?
A	When Ricky Guarte was able to push the door, that is the time I go (sic) downstairs and got my bolo and at that time the body of Ricky Guarte was at the entrance of the door and accidentally the bolo reached him.
Q	Where did you get the bolo?
A	I got the bolo in the post or wall of our house.
Q	Was Ricky Guarte hit the first time you boloed him?
A	Not hacking but accidentally.
Q	What do you mean by accidentally?
A	Because when Ricky Guarte pushed the door and unbalance himself (sic) the bolo which I was carrying hit him accidentally.
Q	Where was he hit by the bolo you were carrying?
A	In the stomach.[17]
	…
Q	And since you were at the left side of the door, your right hand was at the center part of the door, correct?
A	No, Sir.
Q	Where was your right hand?
A	Holding a bolo.
Q	Where, in what part of the door?
A	Right side.
Q	When Ricky Guarte was pushing the door, the door was not opened?
A	It was opened.
Q	It was opened because you opened the door, correct?
A	No, Sir.
Q	Now, why was it opened?
A	Because he was pushing it.
Q	With his left hand?
A	With his both hands and body.
Q	Now, when he fell down because, according to you, he losses (sic) his balance, the left side of the body was the first to fell (sic) down, correct?
A	Yes, Sir.
Q	You are sure of your answer now Mr. Toledo?
A	Yes, Sir.
Q	Now, and while holding that bolo, you are doing that in [an] upward position, correct?
A	No, Sir, pointing the door.
Q	Yes, you are pointing the tip of your bolo to the door upward, correct?
A	No, Sir, steady pointing to the door.
Q	Now, when the door was opened, your bolo did not hit any part of that door, correct?
A	"Ginaiwas ko ang sunrang," meaning I was able to get away from hitting any part of the door.
Q	The question Mr. Toledo is simple, while the door was opened and while you were pointing directly your bolo at the door, not any part of the door hit the bolo (sic), correct?
ATTY. FORMILLEZA:
	It was a valid answer, it did not hit any part of the door.
COURT:
	Answer.
A	No, Sir.
PROS. FRADEJAS continuing:
Q	You were only about five inches away from your door while pushing it, correct?
A	Yes, Sir.
Q	Now, when the door was pushed already by Ricky Guarte, not any part of your body hit the door, correct?
A	No, Sir.[18]

The petitioner also testified that the victim was armed with a balisong and threatened to kill him as the said victim pushed, with his body and hands, the fragile door of his house:

Q	Where were you when you saw Ricky went out?
A	I was at the door.
Q	Did Ricky proceed to the door where you were?
A	Yes, Sir.
Q	What did he do, if any?
A	He drew his fan knife or balisong and asked me what do you like, I will stab you?
Q	What did you do?
A	I told him I have not done you anything wrong, I am only scolding you or telling you not to make noise.
Q	What, if any, did Ricky Guarte do to you?
A	He pushed the door.
Q	Whose door did he push?
A	My own door.
Q	Where were you when he pushed the door?
A	Inside our house.[19]

We find the testimony of the petitioner incredible and barren of probative weight.

First.  If the testimony of the petitioner is to be believed, the force of the struggle between him and the victim would have caused the door to fall on the petitioner.  However, the petitioner failed to adduce real evidence that the door of his house was destroyed and that he sustained any physical injuries,^[20] considering that he was only five inches away from the door.

Second.  If the door fell to the sala of the house of the petitioner, the victim must have fallen on top of the door.  It is incredible that the bolo of the petitioner could have hit the stomach of the victim.  The claim of the petitioner that he managed to step aside and avoid being crushed by the door belies his claim that the bolo accidentally hit the victim on the stomach.

Third.  When he surrendered to the barangay captain and to the policemen, he failed to relate to them that his bolo accidentally hit the stomach of the victim:

Q	Now, that very night when you said Ricky Guarte was accidentally hit by your bolo, you did not surrender to the police, correct?
A	I surrendered to the barangay captain at one o'clock in Panique, in the afternoon.
Q	Now, you only surrendered to the police when a certain person advised you to surrender, correct?
A	On my own volition, I surrendered to the barangay captain.
Q	You did not narrate the incident to the barangay captain whom you have surrendered, correct?
A	No, Sir.
Q	When you were brought to the municipal jail, you did not also narrate to the police what happened, correct?
A	No, Sir.
Q	You just remained silent thinking of an excuse that happened that evening of September 16, 1995, correct?
A	No, Sir.[21]

Fourth.  There is no evidence that the petitioner surrendered either the bolo that accidentally hit the victim or the balisong held by the deceased to the barangay captain or the police authorities.  Such failure of the petitioner negates his claim that his bolo accidentally hit the stomach of the victim and that he acted in self-defense.^[22]

Fifth.  To prove self-defense, the petitioner was burdened to prove the essential elements thereof, namely: (1) unlawful aggression on the part of the victim; (2) lack of sufficient provocation on the part of the petitioner; (3) employment by him of reasonable means to prevent or repel the aggression.  Unlawful aggression is a condition sine qua non for the justifying circumstances of self-defense, whether complete or incomplete.^[23] Unlawful aggression presupposes an actual, sudden, and unexpected attack, or imminent danger thereof, and not merely a threatening or intimidating attitude.^[24] We agree with the ruling of the CA that the petitioner failed to prove self-defense, whether complete or incomplete:

The evidence on record revealed that there is no unlawful aggression on the part of Ricky.  While it was established that Ricky was stabbed at the doorstep of appellant's house which would give a semblance of verity to appellant's version of the incident, such view, however, is belied by the fact that Ricky arrived at appellant's house unarmed and had only one purpose in mind, that is, to ask appellant why he threw stones at his (Ricky's) house.  With no weapon to attack appellant, or defend himself, no sign of hostility may be deduced from Ricky's arrival at appellant's doorstep.  Ricky was not threatening to attack nor in any manner did he manifest any aggressive act that may have imperiled appellant's well-being.  Ricky's want of any weapon when he arrived at appellant's doorstep is supported by the fact that only one weapon was presented in court, and that weapon was the bolo belonging to appellant which he used in stabbing Ricky.  Thus, appellant's version of the events does not support a finding of unlawful aggression.  In People vs. Pletado, the Supreme Court held:

"xxx (F) or aggression to be appreciated, there must be an actual, sudden, [un]expected attack or imminent danger thereof, and not merely a threatening or intimidating attitude (People vs. Pasco, Jr., supra, People vs. Rey, 172 SCRA 149 [1989]) and the accused must present proof of positively strong act of real aggression (Pacificar vs. Court of Appeals, 125 SCRA 716 [1983]).  Unlawful aggression must be such as to put in real peril the life or personal safety of the person defending himself or of a relative sought to be defended and not an imagined threat."

Appellant was not justified in stabbing Ricky.  There was no imminent threat to appellant's life necessitating his assault on Ricky.  Unlawful aggression is a condition sine qua non for the justifying circumstance of self-defense.  For unlawful aggression to be appreciated, there must be an actual, sudden, unexpected attack or imminent danger thereof, not merely a threatening or intimidating attitude.  In the absence of such element, appellant's claim of self-defense must fail.

Further, appellant's plea of self-defense is not corroborated by competent evidence.  The plea of self-defense cannot be justifiably entertained where it is not only uncorroborated by any separate competent evidence but is in itself extremely doubtful.^[25]

Sixth.  With the failure of the petitioner to prove self-defense, the inescapable conclusion is that he is guilty of homicide as found by the trial court and the CA.  He cannot even invoke Article 12, paragraph 4 of the Revised Penal Code.^[26]

IN LIGHT OF ALL THE FOREGOING, the petition is DENIED.  The assailed decision of the Court of Appeals is AFFIRMED.  Costs against the petitioner.

SO ORDERED.

Puno, (Chairman), Austria-Martinez, and Tinga, JJ., concur.
Chico-Nazario, J., on leave.

---

^[1] Penned by Associate Justice Bernardo P. Abesamis (retired), with Associate Justices Juan Q. Enriquez, Jr. and Edgardo F. Sundiam, concurring.

^[2] Penned by Judge Francisco F. Fanlo, Jr.

^[3] CA Rollo, p. 39.

^[4] Id. at 93-96.

^[5] Exhibit "A."

^[6] CA Rollo, p. 47.

^[7] Id. at 31.

^[8] Rollo, p. 39.

^[9] Id. at 15.

^[10] See Chua v. Court of Appeals, 401 SCRA 54 (2003); Roxas v. Court of Appeals, 391 SCRA 351 (2002); Bacaling v. Muya, 380 SCRA 714 (2002).

^[11] People v. Javier, 377 SCRA 300 (2002).

^[12] Bishop, A Treatise on Criminal Law, Vol. 1, 9th ed., pp. 559-560.

^[13] Reyes, The Revised Penal Code, Vol. 1, 1970 ed., p. 149.

^[14] Id. at 213.

^[15] Id. at 214.

^[16] Jarco Marketing Corporation v. Court of Appeals, 321 SCRA 375 (1999).

^[17] TSN, 4 September 1998, p. 6.

^[18] TSN, 21 October 1998, pp. 9-10.

^[19] TSN, 4 September 1998, p. 5.

^[20] TSN, 21 October 1998, p. 15.

^[21] Id. at 13-14.

^[22] People v. Camacho, 359 SCRA 200 (2001).

^[23] Ibid.

^[24] People v. Cario, 288 SCRA 404 (1998).

^[25] Rollo, pp. 62-63.

^[26] People v. Cario, supra.