G.R. No. 11718 , October 31, 1916
THE UNITED STATES, plaintiff-appellee, vs. LORENZO MACASAET, defendant-appellant.

FACTS:
On the night of April 10, 1915, the accused, Lorenzo Macasaet, was standing outside a neighbor’s house discussing his upcoming marriage. Without warning, Raymundo Briones approached him from behind and struck him on the shoulders with a cane. Briones was also armed with a heavy iron whip attached to his wrist. The assault was motivated by jealousy, as Briones was a rival for the hand of Macasaet’s betrothed. In response, Macasaet immediately drew a pocketknife and stabbed Briones several times, resulting in Briones’s death. At trial, the court found that while there was unlawful aggression and no provocation on Macasaet’s part, there was no “reasonable necessity for the means employed” to repel the assault. Consequently, Macasaet was convicted of homicide but was given a penalty one degree lower under Article 86 of the Penal Code, sentencing him to eight years and one day of prision mayor.

ISSUE:
Whether the accused acted in complete self-defense, thereby exempting him from criminal liability under Article 8(4) of the Penal Code.

RULING:
The Supreme Court REVERSED the trial court’s judgment and ACQUITTED Lorenzo Macasaet. The Court held that all the conditions for complete self-defense under Article 8(4) were present:
1. Unlawful Aggression: The sudden, unprovoked, and unexpected attack from behind by Briones constituted unlawful aggression.
2. Reasonable Necessity of the Means Employed: Given the circumstancesa surprise attack at night, by an assailant armed with a cane and a heavy iron whip, with a motive of jealousythe use of a pocketknife, the only weapon immediately available to Macasaet, was reasonably necessary to repel the assault. The Court emphasized that the accused could reasonably believe his life was in danger.
3. Lack of Sufficient Provocation: There was no evidence that Macasaet provoked the attack.

The Court disagreed with the trial judge’s finding that the means used were not reasonably necessary. It ruled that Macasaet acted in legitimate self-defense and was therefore exempt from criminal liability. He was ordered to be set at liberty immediately.