A warrantless arrest in flagrante delicto is lawful when police officers, from a close distance, observe overt acts indicating that the accused are committing or attempting to commit a crime, such as the handling and exchange of suspected illegal drugs; the subsequent search incidental to such lawful arrest is valid, and the seized items are admissible. Substantial compliance with the chain of custody rule under Section 21 of Republic Act No. 9165, as amended, is sufficient if the integrity and evidentiary value of the seized drugs are preserved, and justifiable grounds for non-compliance (such as safety concerns and unavailability of all required witnesses despite diligent efforts) are established, especially when dealing with a substantial quantity of drugs that negates the likelihood of planting or tampering.

The case arose from an anti-drug operation called "Oplan Galugad" conducted by police operatives in Caloocan City. This operation was part of the broader governmental campaign against illegal drugs, targeting areas known for drug activities. The accused-appellants were apprehended during this specific operation.

• On June 15, 2016, around 5:00 p.m., police operatives, including PO1 Alcova and PO1 Lacson, were conducting "Oplan Galugad" in Phase 12, Barangay 188, Tala, Caloocan City.
• From about 15 meters away, they noticed accused-appellants Azis and Macadato, each carrying a sling bag.
• As PO1 Alcova drew closer (about 1.5 meters away), he heard Azis tell Macadato, "eto pa yung tamok galing kay Patak."
• PO1 Alcova then saw Azis take out a plastic bag of suspected shabu and hand it to Macadato, who immediately put it in his own sling bag.
• PO1 Alcova apprehended both Azis and Macadato. He seized Azis's sling bag, finding a bundle of suspected shabu (five knot-tied plastic bags totaling 491.69 grams) and a firearm.
• PO1 Lacson seized Macadato's sling bag, which contained plastic sachets of suspected shabu (six heat-sealed plastic sachets totaling 131.09 grams).
• PO1 Alcova marked the items seized from Azis, and PO1 Lacson marked those from Macadato at the place of arrest.
• Due to a gathering crowd blocking their way, the officers immediately left the area with the accused-appellants and seized items and proceeded to their office.
• At the police station, the items were turned over to PO2 Pascual, the investigator on duty.
• Inventory and photography were conducted in the presence of the accused-appellants and a media representative, Bernard Ariate. Efforts to secure a DOJ representative and an elected public official were unsuccessful as it was past office hours (around 10:30 p.m.).
• PO2 Pascual submitted the seized items to the NPD Crime Laboratory. Forensic Chemist Cejes examined the specimens, which tested positive for methamphetamine hydrochloride.
• Accused-appellants interposed the defense of frame-up, claiming police officers forcibly entered their homes, planted evidence, and arrested them without cause.

• The warrantless arrest was illegal as they were not committing any crime when apprehended.
• The search conducted incidental to the arrest was therefore invalid, and the seized items were inadmissible as fruit of the poisonous tree.
• The apprehending officers failed to comply with the chain of custody requirements under Section 21 of Republic Act No. 9165, particularly the conduct of inventory and photography at the place of arrest and the absence of a DOJ representative and an elected public official during the inventory.
• They were victims of a frame-up by the police officers.

• The warrantless arrest was lawful as the accused-appellants were caught in flagrante delicto illegally possessing dangerous drugs.
• The subsequent search was a valid incidental search to a lawful arrest, making the seized drugs admissible.
• There was substantial compliance with the chain of custody rule. The inventory and photography were conducted at the police station due to the hostile crowd and safety concerns at the arrest site.
• Efforts were made to secure the presence of all required witnesses, but only a media representative was available due to the late hour.
• The integrity and evidentiary value of the seized drugs were preserved.
• The defense of frame-up is unsubstantiated and a common defense in drug cases, especially given the large volume of drugs seized.

• Whether the warrantless arrest of the accused-appellants was valid.
• Whether the search and seizure of the drugs were valid.
• Whether the chain of custody over the seized drugs was properly established.
• Whether the guilt of the accused-appellants for illegal possession of dangerous drugs was proven beyond reasonable doubt.

• Yes, the warrantless arrest was valid. The Court found that PO1 Alcova, from a close distance of 1.5 meters, heard Azis utter the word "tamok" (known to refer to shabu) and saw Azis hand a plastic bag containing white crystalline substances to Macadato. These overt acts constituted probable cause for PO1 Alcova to believe that accused-appellants were committing a crime (in flagrante delicto).
• Yes, the search and seizure were valid. Being incidental to a lawful in flagrante delicto arrest, the search of the accused-appellants' sling bags and the seizure of the drugs were permissible without a warrant.
• Yes, the chain of custody was substantially complied with. The marking was done immediately at the place of arrest. The inventory and photography at the police station were justified due to the gathering crowd posing a safety risk. Efforts to secure all insulating witnesses were made, and the presence of a media representative, coupled with the justifiable reasons for the absence of others (late hour, unavailability), and the preservation of the integrity of the large volume of seized drugs, constituted substantial compliance. The four links in the chain of custody were sufficiently established.
• Yes, the guilt of the accused-appellants was proven beyond reasonable doubt. All elements of illegal possession of dangerous drugs were established. The defense of frame-up was deemed weak and unsubstantiated, especially considering the substantial quantity of shabu (622.78 grams total) seized, which negated the likelihood of planting. The positive testimonies of the police officers prevailed over the accused-appellants' denial. The appeal was dismissed, and the Court of Appeals' decision affirming conviction was affirmed.

• In Flagrante Delicto Arrest — A warrantless arrest is lawful when, in the presence of the peace officer, the person to be arrested has committed, is actually committing, or is attempting to commit an offense (Rule 113, Section 5(a), Rules of Criminal Procedure). Applied here, the Court found that PO1 Alcova personally witnessed Azis uttering "tamok" and handing a plastic bag of suspected shabu to Macadato, justifying their immediate warrantless arrest as they were caught in the act of illegal possession of dangerous drugs.
• Search Incidental to Lawful Arrest — A person lawfully arrested may be searched for dangerous weapons or anything which may have been used or constitute proof in the commission of an offense without a search warrant. This search may extend beyond the person to include the premises or surroundings under his immediate control. Applied here, the search of the accused-appellants' sling bags, which yielded the shabu, was deemed valid as it was conducted contemporaneously with and as an incident to their lawful in flagrante delicto arrest.
• Chain of Custody Rule (Section 21, RA 9165, as amended by RA 10640) — This rule outlines the procedure for the seizure, custody, and disposition of confiscated illegal drugs to ensure their integrity and evidentiary value. It requires immediate inventory and photography in the presence of the accused, a media representative or DOJ representative, and an elected public official. Applied here, the Court found substantial compliance despite the inventory and photography being done at the police station (justified by safety concerns) and with only a media representative present (justified by unavailability of others despite efforts and the late hour). The integrity of the seized drugs was deemed preserved.
• Waiver of Illegality of Arrest — Any objection to an arrest without a warrant must be made before the accused enters their plea; otherwise, the objection is deemed waived. Applied here, the Court noted that accused-appellants failed to question their arrest before plea or during trial, raising it only on appeal, thus waiving any objection to the legality of their arrest.
• Substantial Compliance Doctrine (in relation to Chain of Custody) — Non-compliance with Section 21 of RA 9165 does not ipso facto render the seizure and custody of seized items invalid if (a) there is a justifiable ground for non-compliance, and (b) the integrity and evidentiary value of the seized items are properly preserved. Applied here, the Court found justifiable grounds for deviations (hostile crowd, late hour for witnesses) and that the integrity of the substantial volume of seized drugs was preserved, thus upholding the conviction.
• Presumption of Regularity in Official Duties — In the absence of clear and convincing evidence of ill motive or improper performance of duty, police officers are presumed to have performed their duties regularly. While not explicitly named as a primary basis for conviction, this presumption supports the credibility of the officers' testimonies against the unsubstantiated claim of frame-up. The Court found no showing of ill motive on the part of the apprehending team.
• Defense of Frame-up — Frame-up is a common defense in drug cases that is viewed with disfavor as it can be easily concocted. To be credible, it must be supported by clear and convincing evidence. Applied here, the Court found the accused-appellants' defense of frame-up unsubstantiated, especially given the large quantity of drugs seized, making planting improbable.

• "Where the in flagrante delicto arrest of the accused was lawful, there is no need for a warrant for the seizure of the fruit of the crime as well as for the body search upon him, the same being incidental to a lawful arrest and the search may extend beyond the person of the one arrested to include the premises or surroundings under his immediate control."
• "As a rule, compliance with the chain of custody procedure is strictly enjoined as the same has been regarded not merely as a procedural technicality but as a matter of substantive law... The Court, nonetheless, has recognized that due to varying field conditions, strict compliance with the chain of custody procedure may not always be possible. As such, the failure of the apprehending team to strictly comply with the same would not ipso facto render the seizure and custody over the seized items invalid, provided that the prosecution satisfactorily proves: (a) there is a justifiable ground for non-compliance; and (b) the integrity and evidentiary value of the seized items are properly preserved."
• "Indeed, the likelihood of tampering, loss or mistake with respect to an exhibit is greatest when the exhibit is small and is one that has physical characteristics fungible in nature and similar in form to substances familiar to people in their daily lives." (Quoting Mallillin v. People to distinguish the current case involving a large volume of drugs).
• "Accused-appellants here were caught in the possession of 622.78 grams of shabu. This substantial volume of seized items far outweighed the possibility of planting, tampering, or alteration."
• "An allegation of frame-up by police officers is a common and standard defense in dangerous drugs cases viewed by this Court with disfavor for it can easily be concocted. To substantiate such defense, the evidence must be clear and convincing and should show that the apprehending team was motivated by indecent objective or was not properly performing their duty."

• People v. Pavia — Cited as an example where officers, observing drug use through a window, had probable cause for a warrantless arrest in flagrante delicto and subsequent valid search, similar to PO1 Alcova's observation here.
• Mallillin v. People — Expounded on the rationale for the chain of custody rule, emphasizing its importance for authenticating non-distinctive evidence susceptible to tampering. It was also cited to highlight that the risk of tampering is greatest with small, fungible items, implicitly distinguishing the current case with a large drug volume.
• People v. Taglucop — Cited as precedent where inventory and photography at the nearest police station (instead of the seizure site) were justified due to a gathering crowd, rain, and unsafe conditions, similar to the justification provided by the officers in this case.
• People v. Casa — Clarified that in buy-bust situations or warrantless arrests, inventory and photography may be done at the nearest police station or apprehending team's office, but still require the presence of the accused and insulating witnesses.
• People v. Estabillo — Cited in the context of witness requirements. In Estabillo, the absence of a DOJ prosecutor was noted, but the officers' effort to invite other witnesses was seen as good faith. The current case involved similar efforts and justification for witness absence.
• Ramos v. People — Upheld a conviction despite only a Barangay Captain witnessing the inventory, finding substantial compliance with Section 21 of RA 9165 and unbroken chain of custody. This supports the current ruling's finding of substantial compliance.
• People v. Holgado — Clarified that a minuscule amount of seized drugs is not per se a ground for acquittal but underscores stricter adherence to the chain of custody, contrasting with the present case involving a substantial amount.
• People v. Galon (citing People v. Vallejo) — Referenced for the principle that objections to the legality of a warrantless arrest are waived if not raised before plea.
• People v. Sanchez — Cited for the elements of illegal possession of dangerous drugs.
• Catuiran v. People — Referenced for the purpose of the chain of custody rule: to remove unnecessary doubts concerning the identity of the evidence.
• People v. Kamad — Cited for the four links in the chain of custody.
• People v. Lim — Cited regarding the witness requirements under RA 10640 (amendment to Section 21, RA 9165).
• People v. Boco — Cited regarding the standard of evidence required to substantiate a defense of frame-up.

• Republic Act No. 9165 (Comprehensive Dangerous Drugs Act of 2002), Section 11, Article II — This is the provision under which the accused-appellants were charged and convicted for illegal possession of dangerous drugs.
• Republic Act No. 9165, Section 21 (as amended by Republic Act No. 10640) — This section details the mandatory procedure for the custody and disposition of confiscated, seized, and/or surrendered dangerous drugs, including the requirements for inventory, photography, and the presence of insulating witnesses. Its interpretation and application were central to the case.
• Revised Rules of Criminal Procedure, Rule 113, Section 5(a) — This rule defines when a warrantless arrest is lawful, specifically when a person is caught in flagrante delicto (committing an offense in the officer's presence). This was the basis for upholding the legality of the accused-appellants' arrest.
• Implementing Rules and Regulations of Republic Act No. 9165, Section 21(a) — Further elaborates on the procedure for inventory and photography, allowing it at the nearest police station or office of the apprehending team in warrantless seizures, provided justifiable grounds exist for not doing it at the place of seizure.