G.R. No. 207684 - Philtranco Service Enterprises, Inc. vs. Cual

Benjamin Amansec y Dona (Amansec) was charged on June 18, 2003, with violations of Sections 11 (possession) and 5 (sale) of Article II of Republic Act No. 9165, the Comprehensive Dangerous Drugs Act of 2002.
The charges accused him of unlawfully possessing 0.09 gram of methylamphetamine hydrochloride ("shabu") and unlawfully selling the same amount in Quezon City on June 15, 2003.
Amansec pleaded not guilty to both charges upon arraignment on August 7, 2003.

Police Officers (PO) 1 Alfredo Mabutol, Jr., PO2 Ronald Pascua, PO1 Roderick Valencia, and Police Inspector Oliver Villanueva, with a confidential informant, conducted a buy-bust operation at Amansec's residence in Santos St., Barangay Damayan, San Francisco Del Monte, Quezon City on June 15, 2003, around 11:00 p.m.
Mabutol acted as a poseur-buyer with marked P100.00 buy-bust money. The informant introduced him as a drug addict who wanted to buy shabu.
During the operation, Amansec showed and offered three sachets of white crystalline substance to Mabutol and another buyer, Jerome Pintis.
Pintis bought one sachet, then Amansec sold another sachet to Mabutol in exchange for the buy-bust money.
Upon signal from Mabutol, police arrested Pintis and Amansec. From Amansec, the police recovered the buy-bust money and a sachet of shabu.
The seized plastic sachets were marked with the initials of the police officers who recovered them and were submitted for laboratory examination.

Forensic Chemist Engineer Bernardino M. Banac, Jr. (testimony stipulated), examined the specimens at the Central Police District Crime Laboratory on June 16, 2003.
Chemistry Report No. D-472-03 confirmed the white crystalline substances contained methylamphetamine hydrochloride, a dangerous drug.

Amansec denied the charges, alleging that police officers forcibly searched his room and coerced him to give a name of a big-time drug pusher to take his place, which he could not provide.
He claimed no ill motive against the police officers and denied the allegations as they had no proof.
The RTC tried the two cases jointly on the prosecution's motion.

On August 30, 2006, the RTC found Amansec guilty beyond reasonable doubt of illegal sale of dangerous drugs (Section 5) but acquitted him of illegal possession (Section 11) citing that possession was absorbed in the sale.
The court relied on the consistent, clear, and corroborated testimonies of Mabutol and Pascua.

Amansec appealed, arguing irregularities in the buy-bust operation and inadmissibility of evidence due to procedural lapses, and failure to establish chain of custody.
The Court of Appeals affirmed the RTC ruling on April 15, 2008.
Further appeal to the Supreme Court raised similar contentions regarding witness credibility, procedural non-compliance under Section 21 of RA 9165, and establishment of chain of custody.

Whether the testimonies of the prosecution witnesses regarding the buy-bust operation and sale of illegal drugs were credible.
Whether the non-presentation of the informant and absence of prior surveillance render the buy-bust operation invalid.
Whether the failure of police officers to comply strictly with Section 21 of Republic Act No. 9165, regarding physical inventory and photographing of seized drugs and presence of witnesses, invalidates the evidence and vitiates the arrest.
Whether the chain of custody of the seized dangerous drugs was properly established.
Whether the evidence was sufficient to convict Amansec for violation of Section 5, Article II of R.A. 9165, for illegal sale of dangerous drugs.