Before the Court, appellant seeks to appeal the Decision^[1] dated August 13, 2009 of the Court of Appeals in CA-G.R. CR.-H.C. No. 03337 entitled, People of the Philippines v. Marissa Castillo y Alignay, which affirmed the Decision^[2] dated November 9, 2007 of the Regional Trial Court (RTC) of Pasig City, Branch 154, in Criminal Case Nos. 15167-D and 15168-D.  The trial court convicted appellant Marissa Castillo y Alignay of violation of Section 5 and Section 11 (sale and possession of illegal drugs, respectively), Article II of Republic Act No. 9165 or the Comprehensive Dangerous Drugs Act of 2002.

In Criminal Case No. 15167-D, appellant was charged in an Information^[3] that read:

On or about October 24, 2006, in Pasig City, and within the jurisdiction of this Honorable Court, the accused, not being lawfully authorized by law, did then and there willfully, unlawfully and knowingly sell, deliver and give away to PO2 Thaddeus Santos, a police poseur buyer, one (1) heat-sealed transparent plastic bag containing four centigram (0.04 gram) of white crystalline substance, which was found positive to the test for methylamphetamine hydrochloride, a dangerous drug, in violation of the said law.

While the pertinent portion of the Information^[4] filed in Criminal Case No. 15168-D stated:

On or about October 24, 2006, in Pasig City, and within the jurisdiction of this Honorable Court, the accused, not being lawfully authorized to possess any dangerous drug, did then and there willfully, unlawfully and feloniously have in his [sic] possession and under his [sic] custody and control two (2) heat sealed transparent bags each containing four (4) centigram (0.04 gram) of white crystalline substance, which was found positive to the test for methylamphetamine hydrochloride, a dangerous drug, in violation of the said law.

Upon arraignment, appellant entered pleas of "NOT GUILTY" to both charges.  Afterwards, trial followed with the prosecution presenting Police Officer (PO) 2 Thaddeus Santos (PO2 Santos) and PO1 Grace Chavez (PO1 Chavez) as witnesses.  On the other hand, appellant and her daughter, Marinell Castillo, took to the witness stand for the defense.

The versions of the prosecution and the defense regarding the events surrounding the arrest and detention of appellant were summarized in the November 9, 2007 Decision of the trial court as follows:

While on duty at the drug enforcement unit of the Eastern Police District, a confidential informant (CI) came and informed PO2 Santos and his colleagues at the said office about the illegal activity of the accused Marissa Castillo and one alias "Ompong" who were reported to be selling shabu along J.B. Miguel St., Brgy. Bambang, Pasig City. Upon receiving the information, PSI Hoover Pascual, the team leader of the drug enforcement unit conducted a briefing to discuss the details of the buy bust operation that would be undertaken against the accused. PO1 Santos was designated as the poseur buyer and for this purpose was given two (2) pieces of Php100.00 bills (Exhibit[s] F-1 and F-2) by PSI Pascual. PO1 Santos put his initials "TS" on the two zeroes appearing on the right side of the bills. PO1 Grace Chavez was designated as the immediate back up of PO1 Santos. Thereafter, PO2 Quinton, the police investigator assigned to the team, prepared a pre-operation report (Exhibit "D") for the PDEA and a Certificate of Coordination (Exhibit "E") to show that the team coordinated with the PDEA.

At about 8:45 o'clock in the evening of the same day, the team headed by PSI Hoover Pascual with PO3 Florentino, PO3 Rioja, PO2 Quinton, PO1 Grace Chavez and PO2 Santos as members were dispatched together with the CI to the target area at J.B. Miguel St., Brgy. Bambang, Pasig City on board two (2) vehicles. The police team parked their vehicles a block away from the target place. Thereafter, the CI was ordered to look for Marissa C. Castillo and alias Ompong. After a few minutes, the CI came back and told the police officers that he was able to locate Marissa Castillo and alias Ompong. With this information, PSI Hoover Pascual instructed his team to proceed with the planned operation, whereupon, PO2 Santos and PO1 Grace Chavez, together with the CI, proceeded to J.B. Miguel St., Brgy. Bambang, with the other members following them. Upon seeing Marissa, the CI introduced PO2 Santos and PO1 Grace Chavez to Marissa as potential buyers. After the introduction, the CI asked Marissa "meron ka ba ngayon" referring to shabu. In reply, Marissa said "magkano ang kukunin ninyo" to which the CI replied. "pabili ng dos" and Marissa answered "meron" after which she brought out three (3) plastic sachets and then gave one of the plastic sachets to PO2 Santos.

PO2 Santos examined the plastic sachet given to him after which he scratched his head with his right hand which was the pre-arranged signal to signify that the sale had been consummated. PO2 Santos and his companions then introduced themselves as police officers after which PO2 Santos grabbed the left hand of Marissa Castillo. PO2 Santos was able to recover the Php200.00 buy bust money from the left hand of Marissa and the two other plastic sachets (Exhibits G-1 and G-2) containing suspected shabu. Marissa's companion, however, was able to run away.

After PO2 Santos had arrested accused Castillo, he informed her of her rights and then put markings on the plastic sachets confiscated from the accused. Thereafter, the accused was brought to the office of the SDEU while the plastic sachets confiscated from the accused were brought to crime laboratory for examination. The examination shows that the contents of the plastic sachets tested positive for shabu (Exhibit "B" Physical Science Report No. D-486-06-E). PO2 Santos identified the accused Marissa Castillo in open court.

On cross-examination, PO2 Santos was firm in saying that he gave the buy bust money to Marissa Castillo after the latter had handed the illegal substance to him.

Back-up operative PO1 Grace Chavez confirmed the testimony given by her colleague PO2 Santos. She said that she was part of the buy bust operation conducted by the police operatives headed by PSI Pascual against the accused Marissa Castillo at J.B. Miguel St., Bambang, Pasig City on October 24, 2006. She also confirmed the details of the operations as recounted by her colleague PO1 Santos. She said that after the operation was planned, the team proceeded to the target area on board two vehicles at about 8:30 o'clock in the evening; that upon arriving at the place, their CI was instructed to check if the suspect was in the area; that after 15 minutes the CI returned and gave the information that Marissa Castillo was there in the area talking to a male person; that thereafter, PSI Pascual ordered her and PO2 Santos, together with the CI to buy shabu from the accused; that upon seeing the accused Marissa Castillo, the CI introduced them as regular customers to her; that PO2 Santos handed the Php200.00 buy bust money to Marissa Castillo and that after Marissa received the money, she handed a plastic sachet to PO2 Santos after which she and PO2 Santos introduced themselves to the accused Marissa Castillo as police officers.

PO1 Chavez categorically said that she saw PO2 Santos hold the left hand of Marissa Castillo. Confiscated by PO2 Santos from Marissa Castillo were two plastic sachets of shabu and the buy bust money. This was in addition to the plastic sachet that was sold by PO2 Santos to the accused Marissa. She also said that the transaction took place on an alley near the house of the accused about 5 meters away from the main road.

PO^[1] Chavez also identified the accused Marissa Castillo in open court.

As expected, Marissa Castillo denied the charges leveled against her for illegal sale and illegal possession of shabu. She testified that on October 26, 2006 at around 6:40 o'clock in the evening, while she was walking in an alley on her way home, a man touched her shoulder. The accused would later come to know that man as PO2 Thaddeus Santos. With PO2 Santos at the time were two other male persons. After PO2 Santos touched Castillo's shoulder, PO2 Santos asked if she was Marissa Castillo to which the accused said "yes". After that PO2 Santos asked Marissa to go with them to her house as they would just ask something from her. x x x. Thus, Marissa and the policemen went to her house. When they arrived there, Marissa was greatly surprised upon seeing nine (9) persons inside her house, including police officer Mary Grace Chavez and some other police officers. The two male persons who accompanied Marissa Castillo to her house told the police officer who were there "eto na si Marissa Castillo" after which PO2 Grace Chavez approached Marissa and frisked her but nothing was recovered from her possession. The policemen also searched the house prompting Marissa to ask the policemen why they were searching her house but the policemen just ignored Marissa. Marissa was frisked by one of the policemen who said "ilabas mo iyan". At that point, Marissa's eldest daughter by the name of Marinel was also inside the house watching. After Marissa was frisked, one of the policemen said "ilabas mo na iyan".

After the policemen finished searching Marissa's house, Marissa heard one of them say "wala, wala" and another one saying "dalhin na iyan". Marissa and her daughter Marinel were then brought out of the house and then brought to the Eastern Police District headquarters (EPD). At the EPD headquarters, the police officers asked Marissa to cooperate with them and to point to persons selling shabu. Marissa, however, demurred saying that she did not know what the policemen were talking about and that she could not provide them any assistance. This upset the policemen who then told Marissa "ayaw mong makipagtulungan sa amin, bahala ka". After that, one of the police officers asked Marissa's daughter to go home and gave her Php20.00 as fare money. Marissa, on the other hand, was detained because she refused to cooperate with the police. Marissa said that she learned that charges for violation of Sections 5 and 11 of R.A. 9165 were filed against her only during her inquest. Marissa Castillo insisted during the inquest that the charges against her were not true but charges were nonetheless filed against her by the police.

Marinel Castillo, the daughter of the accused, corroborated in some details the testimony of her mother. She said that at around 6:30 o'clock in the evening of October 24, 2006 while she was in their house, she heard someone trying to open their door. When she peeped through the window she saw about nine (9) men outside who entered their house. Once inside the men started searching the house. Marinel asked the men to whom she would later know as police officers, why they entered their house but the police officers just ordered her to be quiet and to just sit down. After the police had searched the house, a policeman approached her and frisked her. Nothing, however, was recovered from her possession. Marinel claimed that the police officers took a video camera, three (3) cellfones and other appliances from their house which the policemen did not return anymore. Marinel testified that while the police were in their house, one of the police officers whom she identified as PO2 Santos asked Marinel the whereabouts of her mother, the accused Marissa Castillo. After Marinel had informed PO2 Santos that her mother was in the market, PO2 Santos went out of the house together with another man. After that, Marinel's mother, the accused Marissa, arrived in their house together with PO2 Santos and the man who accompanied him. Marinel said that when her mother arrived, Marissa was surprised to see many people inside the house, with their things scattered all over the place. Marinel testified that a policeman frisked her mother. Recovered from her were some coins but the police officer by the name of Florentino still said "dalhin na iyan". Marinel heard her mother ask the policeman where they would be bringing her and Marinel. Officer Florentino replied "ayaw mo rin lang ilabas dalhin na kayo". After that, the police officers brought Marinel and the accused Marissa Castillo to the Eastern Police District. At the police station, PO2 Santos, Florentino and some other police officers talked with her mother, the accused Marissa. Thereafter, a police officer approached Marinel and gave her Php20.00 for her fare in going home.

Marinel admitted that she did not know what happened from the time PO2 Santos left their house to look for her mother up to the time PO2 Santos returned with her mother.^[5]

At the end of trial, the trial court rendered a verdict convicting appellant of the charge of sale of illegal drugs as well as the charge of possession of illegal drugs.  The dispositive portion of the assailed November 9, 2007 Decision reads:

WHEREFORE, premises considered, judgment is hereby rendered in Criminal Case No. 15167-D finding the accused MARISSA CASTILLO y Alignay GUILTY beyond reasonable doubt of violation of Section 5, Article II of R.A. 9165 (sale of dangerous drugs) and she is hereby sentenced to suffer the penalty of LIFE IMPRISONMENT. She is also ordered to pay a fine of Five Hundred Thousand Pesos (Php500,000.00).

In Criminal Case No. 15168-D, the accused MARISSA CASTILLO y Alignay is hereby found GUILTY beyond reasonable doubt of the crime of Violation of Section 11, Article II, R.A. 9165 for possessing shabu, a prohibited drug, and she is hereby sentenced to suffer the indeterminate penalty of TWELVE (12) YEARS and ONE (1) DAY to FIFTEEN (15) YEARS and ONE (1) DAY imprisonment.

She is also ordered to pay a fine of Four Hundred Thousand Pesos (Php400,000.00).

Considering the judgment rendered by the Court, the immediate commitment of the accused to the Correctional Institute for Women, Mandaluyong City is hereby ordered.

The illegal substance subject of the Information is ordered to be turned over forthwith to the Philippine Drug Enforcement Agency (PDEA) for proper action and disposition.^[6]

Appellant then elevated the case to the Court of Appeals in the expectation of a different ruling; however, the appellate court considered her appeal as devoid of merit and affirmed the ruling of the trial court's judgment.  The dispositive portion of the assailed August 13, 2009 Decision of the Court of Appeals is as follows:

WHEREFORE, the foregoing considered, the appeal is hereby DISMISSED and the assailed Decision AFFIRMED, in toto.^[7]

Hence, appellant filed the present appeal wherein she submitted the following assignment of errors for consideration:

THE TRIAL COURT GRAVELY ERRED IN FINDING THE ACCUSED-APPELLANT GUILTY OF THE CRIME CHARGED NOTWITHSTANDING THE FAILURE OF THE PROSECUTION TO PROVE HER GUILT BEYOND REASONABLE DOUBT.^[8]

THE COURT OF APPEALS GRAVELY ERRED IN FINDING THE ACCUSED-APPELLANT GUILTY OF THE CRIME CHARGED NOTWITHSTANDING THE PROSECUTION'S FAILURE TO PROVE HER GUILT BEYOND REASONABLE DOUBT.^[9]

Appellant argues that the police officers who apprehended her failed to strictly comply with the procedural requirements of Section 21(1), Article II of Republic Act No. 9165, specifically, the failure to take photographs and to make an inventory of the seized evidence, and the lack of participation of the representatives from the media, the Department of Justice (DOJ), and any elected public official in the operation.  Failing in such regard, appellant insists that the prosecution's case should necessarily fall and she be acquitted of all charges against her as the chain of custody of the seized illegal drugs was not properly established.

We are not persuaded.

In the instant petition, appellant requests this Court to carry out an inquiry on whether or not the arresting officers strictly complied with the requirements set forth by Section 21(1), Article II of Republic Act No. 9165, the text of which provides:

SECTION 21. Custody and Disposition of Confiscated, Seized, and/or Surrendered Dangerous Drugs, Plant Sources of Dangerous Drugs, Controlled Precursors and Essential Chemicals, Instruments/Paraphernalia and/or Laboratory Equipment. The PDEA shall take charge and have custody of all dangerous drugs, plant sources of dangerous drugs, controlled precursors and essential chemicals, as well as instruments/paraphernalia and/or laboratory equipment so confiscated, seized and/or surrendered, for proper disposition in the following manner:

(1) The apprehending team having initial custody and control of the drugs shall, immediately after seizure and confiscation, physically inventory and photograph the same in the presence of the accused or the person/s from whom such items were confiscated and/or seized, or his/her representative or counsel, a representative from the media and the Department of Justice (DOJ), and any elected public official who shall be required to sign the copies of the inventory and be given a copy thereof[.]

At the outset, it should be noted that appellant did not raise the issue of the alleged non-compliance with the aforementioned procedural rule when the case was still being heard in the trial court.  In People v. Robelo,^[10] we ruled that this assertion must be argued before the trial court and not on appeal for the first time, thus:

Indeed[,] the police officers' alleged violations of Sections 21 and 86 of Republic Act No. 9165 were not raised before the trial court but were instead raised for the first time on appeal. In no instance did appellant least intimate at the trial court that there were lapses in the safekeeping of seized items that affected their integrity and evidentiary value. Objection to evidence cannot be raised for the first time on appeal; when a party desires the court to reject the evidence offered, he must so state in the form of objection. Without such objection, he cannot raise the question for the first time on appeal.

Nevertheless, we will still pass upon this question considering the gravity of its consequences on the liberty of appellant.  We take this opportunity to reiterate jurisprudence which states that non-compliance with Section 21 does not necessarily render the arrest illegal or the items seized inadmissible because what is essential is that the integrity and evidentiary value of the seized items are preserved which would be utilized in the determination of the guilt or innocence of the accused.^[11]

Moreover, despite the seemingly mandatory language used in the procedural rule at issue, a perusal of Section 21, Article II of the Implementing Rules and Regulations of Republic Act No. 9165 reveals the existence of a clause which may render non-compliance with said procedural rule non-prejudicial to the prosecution of drug offenses, to wit:

SECTION 21. Custody and Disposition of Confiscated, Seized, and/or Surrendered Dangerous Drugs, Plant Sources of Dangerous Drugs, Controlled Precursors and Essential Chemicals, Instruments/Paraphernalia and/or Laboratory Equipment. The PDEA shall take charge and have custody of all dangerous drugs, plant sources of dangerous drugs, controlled precursors and essential chemicals, as well as instruments/paraphernalia and/or laboratory equipment so confiscated, seized and/or surrendered, for proper disposition in the following manner:

(a)    The apprehending officer/team having initial custody and control of the drugs shall, immediately after seizure and confiscation, physically inventory and photograph the same in the presence of the accused or the person/s from whom such items were confiscated and/or seized, or his/her representative or counsel, a representative from the media and the Department of Justice (DOJ), and any elected public official who shall be required to sign the copies of the inventory and be given a copy thereof; Provided, that the physical inventory and photograph shall be conducted at the place where the search warrant is served; or at the nearest police station or at the nearest office of the apprehending officer/team, whichever is practicable, in case of warrantless seizures; Provided, further, that non-compliance with these requirements under justifiable grounds, as long as the integrity and the evidentiary value of the seized items are properly preserved by the apprehending officer/team, shall not render void and invalid such seizures of and custody over said items[.] (Emphasis supplied.)

Essentially, Section 21(1) of Republic Act No. 9165 ensures that the chain of custody of the seized drugs to be used in evidence must be complete and unbroken.  We have defined "chain of custody" as the duly recorded authorized movements and custody of seized drugs or controlled chemicals from the time of seizure/confiscation to receipt in the forensic laboratory to safekeeping to presentation in court for destruction.^[12]

We reiterated the importance of the chain of custody as a means of validating evidence in the recent case of People v. Del Rosario,^[13] where we held:

As a method of authenticating evidence, the chain of custody rule requires that the admission of an exhibit be preceded by evidence sufficient to support a finding that the matter in question is what the proponent claims it to be. It would include testimony about every link in the chain, from the moment the item was picked up to the time it is offered into evidence, in such a way that every person who touched the exhibit would describe how and from whom it was received, where it was and what happened to it while in the witness' possession, the condition in which it was received and the condition in which it was delivered to the next link in the chain. These witnesses would then describe the precautions taken to ensure that there had been no change in the condition of the item and no opportunity for someone not in the chain to have possession of the same.

While testimony about a perfect chain is not always the standard because it is almost always impossible to obtain, an unbroken chain of custody becomes indispensable and essential when the item of real evidence is not distinctive and is not readily identifiable, or when its condition at the time of testing or trial is critical, or when a witness has failed to observe its uniqueness The same standard likewise obtains in case the evidence is susceptible to alteration, tampering, contamination and even substation and exchange. In other words, the exhibit's level of susceptibility to fungibility, alteration or tampering without regard to whether the same is advertent or otherwise not dictates the level of strictness in the application of the chain of custody rule.

In the case at bar, we concur with appellant's assertion that the arresting officers involved were not able to strictly comply with the procedural guidelines stated in Section 21(1), Article II of Republic Act  No. 9165.  However, our affinity with appellant's argument does not sway us towards granting her absolution because, notwithstanding the procedural error, the integrity and the evidentiary value of the illegal drugs used in this case were duly preserved and the chain of custody of said evidence was shown to be unbroken.

With regard to the first link in the chain of custody, the testimony of PO2 Santos confirms the fact that three heat-sealed plastic sachets each containing 0.04 gram of methylamphetamine hydrochloride or shabu were seized from appellant during a buy-bust operation conducted by PO2 Santos, PO1 Chavez and an unnamed confidential informant.  The seized drugs were immediately marked at the place where appellant was apprehended.  The relevant portions of PO2 Santos's testimony follow:

[PROSECUTOR TOLENTINO]
Q	Three (3) plastic sachets were withdrawn by this Marissa, Marissa at the same time checked one and gave it to you, one plastic sachet?
A	Yes, sir.
Q	What did you do?
A	I gave the two (2) pieces of P100.00 bill.
Q	So you handed the money, the P200.00, to this person, a certain Marissa?
A	Yes, sir.
Q	That is after you have been handed the shabu?
A	Yes, sir.
Q	And after the money was given to Marissa or handed to Marissa, what happened next?
A	When I examined the plastic sachet, I gave the pre-arranged signal to my co-operatives.
Q	What was the pre-arranged signal that was given?
A	Scratching my head.
Q	With what hand did you scratch your head?
A	With my right hand.
Q	After you gave the pre-arranged signal, what happened next?
A	We introduced ourselves as policemen.
Q	You first, you introduced yourself as a police officer?
A	Yes, sir, and grabbed the left hand of Marissa.
Q	And after grabbing her by holding her left hand, what happened next?
A	She was surprised and the male companion of Marissa ran away.
Q	What happened to the male companion of Marissa? Were you able to arrest that person?
A	Yes, sir.
Q	What happened when you arrested her?
A	I grabbed her left hand when she got the money and I then got the sachet.
Q	So you got the P200.00 from her left hand and got two more plastic sachets of shabu. Who arrived at that point in time?
A	My back up, Grace Chavez.
Q	What did she do?
A	She joined the arrest by grabbing Marissa.
Q	That person you call Marissa, if that person is presented to you again, can you recognize her?
A	Yes, sir.
Q	Is she present in this courtroom?
A	Yes, sir.
Q	Please come down and tap her shoulder?
A	(Witness stepping down from the witness stand and tapped the shoulder of a person inside the courtroom who when asked gave the name Marissa Castillo.)
Q	You arrested her. What did you tell her after arresting the person named Marissa?
A	We informed her of her rights.
Q	What about the fact of her arrest?
A	Yes, sir, after the arrest.
Q	The specimens that you have confiscated from her, what did you do with them?
A	We marked it at the place where she was arrested.
Q	The subject matter of sale, what did you place as a mark?
A	Her initials, MC.
Q	And the other two plastic sachets recovered after her arrest, what markings did you put?
A	MC
Q	I am showing to you three (3) plastic sachets containing shabu. Will you please go over and tell us which one was the subject matter of sale and which were the plastic sachets which were recovered after her arrest?
A	This is the one bought (witness referring to a plastic sachet with marking MC A-1 and underneath are the words "buy bust evidence").
Q	These were your markings, MC A-1?
A	Yes, sir.
Q	The buy bust evidence?
A	Yes, sir.
Q	There appears to be two plastic sachets containing shabu which were marked MC A-2 and MC A-3. What are these?
A	These are the two plastic sachets confiscated from her left hand.[14]

PO1 Chavez's testimony corroborates PO2 Santos's narrative regarding the arrest and seizure of shabu from appellant.  The pertinent portions of her testimony are quoted here:

[PROSECUTOR TOLENTINO]
Q	When the informant confirmed that the target person, the accused Marissa Castillo, was present thereat, what did you do next, Madam Witness?
A	[Police Senior Inspector] Hoover Pascual ordered us to buy from the suspect.
Q	Who went ahead?
A	PO2 Thaddeus [Santos] and I.
Q	Who accompanied you thereat?
A	The informant.
Q	Where did you place yourself as back-up officer?
A	I was at the left side of PO2 Thaddeus Santos.
Q	After that, what happened next?
A	Then the CI introduced us to the suspect as drug users.
Q	So you were there beside Police Officer Santos all the time?
A	Yes, sir.
Q	At the time this operation was being conducted?
A	Yes, sir.
Q	Tell us, after that operation was conducted and the transfer and sale was made, what happened next?
A	After we were introduced as users, the CI told the suspect that we could be regular customers.
Q	After that, when you were introduced as would be regular buyers, what happened next?
A	Because she was already holding three (3) sachets of shabu. He then handed the money.
Q	Who handed the money?
A	PO2 Thaddeus.
Q	After the handing of the P200.00, what transpired next?
A	After giving her the money, she handed to us one plastic sachet of shabu then we introduced ourselves as police officers.
Q	You said one (1) plastic sachet was handed to whom?
A	To PO2 Thaddeus Santos.
Q	After the handing of the accused of this one plastic sachet to PO2 Thaddeus Santos, what happened next?
A	We introduced ourselves as police officers and presented our IDs.
Q	After you identified yourselves as police officers and showing your IDs, what did you do next?
A	I saw Thaddeus hold the left hand of the suspect and he confiscated the two (2) plastic sachets of shabu and the buy bust money.
Q	And you, when you saw the police poseur buyer PO2 Santos held the hand of the accused containing the plastic sachet and the buy bust money, what did you do?
A	I just watched them and informed Marissa Castillo of her rights and then my companions arrived.
	x x x x
Q	If that person whom you arrested and recovered the plastic sachet containing the shabu and from whom Thaddeus Santos bought shabu, if ever this person is presented to you again, can you recognize this person, Madam Witness?
A	Yes, sir.
Q	Is she present in this courtroom today, Miss Witness?
A	Yes, sir.
Q	Please stand up and tap her on her shoulder.
A	(Witness stepping down from the witness stand and tapped the shoulder of a [woman] who when asked gave the name Marissa Castillo.)
Q	After she was arrested, where did you bring her?
A	At the EPD Headquarters.[15]

The illegal drugs seized from appellant were then turned over to Police Senior Inspector Hoover SM Pascual (PSI Pascual), the team leader and investigator of the buy-bust operation, who prepared and signed a Memorandum^[16] requesting the laboratory examination of the three plastic sachets containing white crystalline substance previously marked by PO2 Santos as "MCA-1," "MCA-2" and "MCA-3," respectively.  This document together with the marked specimens was then transmitted to the Eastern Police District (EPD) Crime Laboratory Office to determine if they contained dangerous drugs. As per Physical Sciences Report No. D-486-06E,^[17] signed by Police Senior Inspector Isidro L. Carino (PSI Carino), the qualitative examination of the contents of the three plastic sachets yielded a positive result for the presence of methylamphetamine hydrochloride or shabu.  The same marked specimens were later identified by PO2 Santos in open court as the same items that he seized from appellant when confronted with them by Prosecutor Conrado Tolentino (Tolentino).  After PO2 Santos positively identified them, Prosecutor Tolentino then requested the trial court that the three plastic sachets containing shabu be marked as Exhibits "G," "G-1," and "G-2," respectively.^[18]  From the foregoing narrative, it is readily apparent that the other links in the chain of custody of the seized illegal drugs have been sufficiently established.

Furthermore, the testimony of PO2 Santos and PO1 Chavez survived the scrutiny of both the trial court judge and the defense counsel and was adjudged to be credible and worthy of belief not only by the trial court but also by the appellate court.  This is significant considering that we have stated in jurisprudence that the successful prosecution of drug cases is dependent, in large part, to the credibility of the police officers who conducted the buy-bust operation.^[19]  In this case, we find no reason to question the credibility of the prosecution witnesses considering that, time and again, we have held that the determination of the credibility of witnesses by the trial court, when affirmed by the appellate court, is accorded full weight and credit as well as great respect, if not conclusive effect.^[20]

With respect to her defense, appellant raised the claim that she was innocent of the charges and was merely framed by the police officers who arrested her.  Nevertheless, in one case, we thoroughly explained why this Court is usually wary of a defense of denial in drug cases, thus:

Further, the testimonies of the police officers who conducted the buy-bust are generally accorded full faith and credit, in view of the presumption of regularity in the performance of public duties. Hence, when lined against an unsubstantiated denial or claim of frame-up, the testimony of the officers who caught the accused red-handed is given more weight and usually prevails. In order to overcome the presumption of regularity, jurisprudence teaches us that there must be clear and convincing evidence that the police officers did not properly perform their duties or that they were prompted with ill-motive.^[21] (Citations omitted.)

Appellant may argue that her denial is not entirely unsubstantiated because the same is corroborated by the testimony^[22] of her daughter, Marinell Castillo.  However, contrasted with the credible and positive testimony of PO2 Santos and PO1 Chavez, the corroborating testimony made by appellant's daughter is given lesser probative value than that of the prosecution's witnesses since this Court has consistently held that the defense of denial or frame-up, like alibi, has been invariably viewed by the courts with disfavor for it can easily be concocted and is a common and standard defense ploy in most prosecutions for violation of the Dangerous Drugs Act.^[23]

Furthermore, we have recently reiterated that we give less probative weight to a defense of alibi when it is corroborated by friends and relatives.^[24] We apply the same principle in the case at bar and declare that for the defense of denial to prosper, like alibi, it is necessary that the corroboration is credible, the same having been offered preferably by disinterested witnesses.  In so doing, we regard the testimony of appellant's daughter, which in no way can be considered as disinterested and unbiased, as invalid corroboration unworthy of belief.

Lacking unprejudiced testimony to support her denial and without her making any allegation as to any ill motive on the part of the police officers who arrested her during a legitimate buy-bust operation, this Court is not inclined  to overturn appellant's conviction for the sale and possession of illegal drugs.

WHEREFORE, premises considered, the Decision dated August 13, 2009 of the Court of Appeals in CA-G.R. CR.-H.C. No. 03337 is AFFIRMED.

SO ORDERED.

Sereno, C.J., (Chairperson), Bersamin, Villarama, Jr., and Reyes, JJ., concur.

---

^[1] Rollo, pp. 2-16; penned by Associate Justice Josefina Guevara-Salonga with Associate Justices Arcangelita M. Romilla-Lontok and Romeo F. Barza, concurring.

^[2] CA rollo, pp. 12-29.

^[3] Records, p. 1.

^[4] Id. at 17.

^[5] CA rollo, pp. 12-18.

^[6] Id. at 20.

^[7] Rollo, p. 16.

^[8] CA rollo, p. 53.

^[9] Rollo, p. 36.

^[10] G.R. No. 184181, November 26, 2012, 686 SCRA 417, 427-428, citing People v. Sta. Maria, 545 Phil. 520, 534 (2007); People v. Hernandez, G.R. No. 184804, June 18, 2009, 589 SCRA 625, 645; People v. Lazaro, Jr., G.R. No. 186418, October 16, 2009, 604 SCRA 250, 274.

^[11] People v. Aneslag, G.R. No. 185386, November 21, 2012, 686 SCRA 150, 163.

^[12] People v. Dumaplin, G.R. No. 198051, December 10, 2012, 687 SCRA 631, 640.

^[13] G.R. No. 188107, December 5, 2012, 687 SCRA 318, 330, citing People v. Guru, G.R. No. 189808, October 24, 2012, 684 SCRA 544, 555-556.

^[14] TSN, April 26, 2007, pp. 9-12.

^[15] TSN, June 21, 2007, pp. 6-9.

^[16] Records, p. 52.

^[17] Id. at 51.

^[18] TSN, April 26, 2007, pp. 11-12.

^[19] People v. Lapasaran, G.R. No. 198820, December 10, 2012, 687 SCRA 663, 673.

^[20] People v. Hambora, G.R. No. 198701, December 10, 2012, 687 SCRA 653, 660, citing People v. Amarillo, G.R. No. 194721, August 15, 2012, 678 SCRA 568, 579.

^[21] Ampatuan v. People, G.R. No. 183676, June 22, 2011, 652 SCRA 615, 628.

^[22] TSN, September 27, 2007.

^[23] People v. Buenaventura, G.R. No. 184807, November 23, 2011, 661 SCRA 216, 226.

^[24] People v. Basallo, G.R. No. 182457, January 30, 2013, 689 SCRA 616, 644.