G.R. No. L-10528; January 27, 1916
THE UNITED STATES, plaintiff-appellee, vs. BONIFACIO MONTEROSO and EUGENIO MONTEROSO, defendants-appellants.

FACTS:
Bonifacio Monteroso and his son Eugenio Monteroso were charged with homicide. The incident occurred during a festivity in Bonifacio’s house. The deceased, while dancing with a young woman (the querida or mistress of one of Bonifacio’s other sons), committed an indecent and lascivious act by placing his hands upon her. This act provoked intense indignation and anger in Bonifacio and his sons, leading to a quarrel that culminated in Bonifacio fatally assaulting the deceased. Eugenio Monteroso participated in the quarrel but his specific involvement in the fatal assault was unclear.

ISSUE:
1. Whether the plea of self-defense by Bonifacio Monteroso is valid.
2. Whether the mitigating circumstance of pasión y obcecación (passion and obfuscation) under Article 9(7) of the Penal Code is applicable to Bonifacio Monteroso.
3. Whether Eugenio Monteroso is guilty as a co-conspirator or principal in the homicide.

RULING:
1. On Self-Defense: The Supreme Court found no evidence to justify the plea of self-defense. The killing was not done in defense of person, but was an unlawful retaliation.
2. On Mitigating Circumstance for Bonifacio: The Court affirmed the trial judge’s finding that the mitigating circumstance of pasión y obcecación was present. The deceased’s indecent and lascivious conduct was a legitimate and natural provocation that produced a powerful impulse of passion and obfuscation in Bonifacio, sufficiently explaining his violent reaction. The Court distinguished this case from U.S. v. Hicks, where the passion arose from jealousy, not from a wrongful act against which the accused could legitimately complain. The fact that the offended woman was a mistress did not justify the deceased’s conduct or lessen the natural indignation it aroused.
3. On the Liability of Eugenio: The Court held that the evidence did not conclusively establish that Eugenio participated in the deadly assault or had knowledge of his father’s intent to commit it. Giving him the benefit of reasonable doubt, he must be acquitted.

DISPOSITIVE:
The judgment of conviction against Bonifacio Monteroso is AFFIRMED, with costs against him. The judgment of conviction against Eugenio Monteroso is REVERSED. He is ACQUITTED and ordered released immediately, with costs de oficio.