People v. Barros, 231 SCRA 57 (1994)
While aboard a bus, two peace officers saw Barros carrying a carton, boarded the bus and seated himself under seat No. 18 after putting the carton under his seat. Before the two peace officers alighted, it being their station, they called peace officer Bongyao to inspect the carton under seat No. 18. After Bongyao inspected the carton, he found out that it contained marijuana and he asked the passengers who the owner of the carton was but nobody answered. Thereafter, Bongyao alighted with the carton and invited Barros to the detachment for questioning as he was the suspected owner of the carton containing marijuana. Barros was convicted of violation of the Dangerous Drugs Act.
Whether or not appellant’s constitutional right against unreasonable searches and seizures had been violated.
YES. The accused is not to be presumed to have waived the unlawful search conducted on the occasion of his warrantless arrest "simply because he failed to object". To constitute a waiver, it must appear first that the right exists; secondly, that the person involved had knowledge, actual or constructive, of the existence of such a right; and lastly, that said person had an actual intention to relinquish the right.
In this case, there existed no circumstance which might reasonably have excited the suspicion of the two (2) police officers riding in the same bus as appellant Barros. There was, in other words, nothing to show that appellant Barros was then in the process of "actually committing" or "attempting to commit" a crime. There was, moreover, nothing on the record that could have reasonably led the two (2) police officers to believe that "an offense [had] in fact just been committed" when appellant Barros boarded the bus at Chackchakan or when he was asked whether he owned the box here involved at the checkpoint in Sabangan. The two (2) police officers, according to the record, had no "personable knowledge of facts indicating that the person to be arrested (appellant Barros) had committed it." There was, in brief, no basis for a valid warrantless arrest. Accordingly, the search and seizure of the carton box was equally non-permissible and invalid. The "fruits" of the invalid search and seizure — i.e., the four (4) kilos of marijuana — should therefore not have been admitted in evidence against appellant Barros.
Kagui Malasugui is not applicable to the instant case, because there the Court explicitly found that there was probable cause for the warrantless arrest of the accused and therefore, the warrantless search effected immediately thereafter was equally lawful.