Edison Sucro was charged with and convicted of violation of Section 4, Article II of the Dangerous Drugs Act, under an Information which reads:

"That on or about the 21st day of March, 1989, in the evening, in the Poblacion, Municipality of Kalibo, Province of Aklan, Republic of the Philippines, and within the jurisdiction of this Honorable Court, the above-named accused, acting as a pusher or broker in the business of selling, administering, delivery, giving away to another and/or distributing prohibited drugs, did then and there wilfully, unlawfully and feloniously and without authority of law have in his possession and control nineteen (19) pieces of marijuana cigarette sticks and four (4) tea bags of dried marijuana leaves which were confiscated from him by the police authorities of Kalibo, Aklan, shortly after having sold one tea bag of dried marijuana leaves to a customer." (Rollo, p. 9)

Upon arraignment, the accused-appellant, assisted by counsel, entered a plea of "not guilty" to the offense charged.  Trial ensued and a judgment of conviction was rendered, the pertinent portion of which reads:

"WHEREFORE, judgment is rendered finding the accused Edison Sucro guilty of the sale of prohibited drug under Section 4, Article II of the Dangerous Drug Act, as amended, and sentencing him to suffer the penalty of life imprisonment, and pay a fine of P20,000, and costs.  He shall be entitled to full credit in the service of his sentence with the period for which he has undergone preventive imprisonment to the date of promulgation of this judgment.  All the items of marijuana confiscated in this case are declared forfeited in favor of the State." (Rollo, p. 41)

From the foregoing judgment of conviction, accused-appellant interposes this appeal, assigning, the following as errors allegedly committed by the court a quo, to wit:

I

THE LOWER COURT ERRED IN ADMITTING AS EVIDENCE FOR THE PROSECUTION EXHIBITS "E" - "E-4", TEA BAGS OF ALLEGED MARIJUANA, TO BE THE CORPUS DELICTI; FURTHERMORE, THAT THE SAME WERE TAKEN WITHOUT THE REQUIRED WARRANT OF SEARCH AND ARREST SINCE THE ACCUSED WAS NOT IN THE ACT OF COMMITTING ANY OFFENSE AT THE TIME OF HIS ARREST.

II

THE LOWER COURT ERRED IN FINDING THE ACCUSED EDISON SUCRO GUILTY OF THE SALE OF PROHIBITED DRUGS UNDER SECTION 4, ARTICLE II, OF THE DANGEROUS DRUGS ACT AND SENTENCING HIM TO SUFFER A PENALTY OF LIFE IMPRISONMENT AND TO PAY A FINE OF P20,000.00.  (Appellant's Brief, p. 1)

The antecedent facts of the case as summarized by the Solicitor General are as follows:

"On March 21, 1989, Pat. Roy Fulgencio, a member of the INP, Kalibo, Aklan, was instructed by P/Lt. Vicente Seraspi, Jr. (Station Commander of the INP Kalibo, Aklan) to monitor the activities of appellant Edison Sucro, because of information gathered by Seraspi that Sucro was selling marijuana.  (p. 6, TSN, May 2, 1989)

As planned, at about 5:00 P.M. on said date, Pat. Fulgencio positioned himself under the house of a certain Arlie Regalado at C. Quimpo Street.  Adjacent to the house of Regalado, about 2 meters away, was a chapel.  Thereafter, Pat. Fulgencio saw appellant enter the chapel, taking something which turned out later to be marijuana from the compartment of a cart found inside the chapel, and then return to the street where he handed the same to a buyer, Aldie Borromeo.  After a while appellant went back to the chapel and again came out with marijuana which he gave to a group of persons.  (pp. 6-8, 15-18, ibid)  It was at this instance that Pat. Fulgencio radioed P/Lt. Seraspi and reported the activity going on.  P/Lt. Seraspi instructed Pat. Fulgencio to continue monitoring developments.  At about 6:30 P.M., Pat. Fulgencio again called up Seraspi to report that a third buyer later identified as Ronnie Macabante, was transacting with appellant.  (pp. 18-19, ibid)

At that point, the team of P/Lt. Seraspi proceeded to the area and while the police officers were at the Youth Hostel at Maagma St., Pat. Fulgencio told P/Lt. Seraspi to intercept Macabante and appellant.  P/Lt. Seraspi and his team caught up with Macabante at the crossing of Mabini and Maagma Sts. in front of the Aklan Medical Center.  Upon seeing the police, Macabante threw something to the ground which turned out to be a tea bag of marijuana.  (pp. 6-8, TSN, June 19, 1989) When confronted, Macabante readily admitted that he bought the same from appellant (Edison Sucro) in front of the chapel.  (p. 6, TSN, May 24, 1989) The police team was able to overtake and arrest appellant at the corner of C. Quimpo and Veterans Sts.  The police recovered 19 sticks and 4 teabags of marijuana from the cart inside the chapel and another teabag from Macabante.  The teabags of marijuana were sent to the PC-INP Crime Laboratory Service, at Camp Delgado, Iloilo City for analysis.  The specimens (Exhibits "G" to "G-18", Exhibits "E" to "E-4") were all found positive of marijuana.  (pp. 4-7, TSN, Sept. 4, 1989)" (Appellee's Brief, pp. 3-6)

As can be seen from the facts, the issue hinges mainly on whether or not the arrest without warrant of the accused is lawful and consequently, whether or not the evidence resulting from such arrest is admissible.

We rule in the affirmative.

The accused-appellant contends that his arrest was illegal, being a violation of his rights granted under Section 2, Article III of the 1987 Constitution.  He stresses that there was sufficient time for the police officers to apply for a search and arrest warrants considering that Fulgencio informed his Station Commander of the activities of the accused two days before March 21, 1989, the date of his arrest.

This contention is without merit.

Section 5, Rule 113 of the Rules on Criminal Procedure provides for the instances where arrest without warrant is considered lawful.  The rule states:

"Arrest without warrant, when lawful. - A peace officer or private person may, without warrant, arrest a person:

(a) When in his presence, the person to be arrested has committed, is actually committing, or is attempting to commit an offense;

(b) When an offense has in fact just been committed, and he has personal knowledge of facts indicating that the person to be arrested has committed it;" (Underscoring supplied)

An offense is committed in the presence or within the view of an officer, within the meaning of the rule authorizing an arrest without a warrant, when the officer sees the offense, although at a distance, or hears the disturbances created thereby and proceeds at once to the scene thereof.  (U. S. v. Fortaleza, 12 Phil. 472 [1909]; and U. S. v. Samonte, 16 Phil. 516 [1910])

The records show that Fulgencio went to Arlie Regalado's house at C. Quimpo Street to monitor the activities of the accused who was earlier reported to be selling marijuana at a chapel two (2) meters away from Regalado's house.

Fulgencio, within a distance of two meters saw Sucro conduct his nefarious activity.  He saw Sucro talk to some persons, go inside the chapel, and return to them and exchange some things.  These, Sucro did three times during the time that he was being monitored.  Fulgencio would then relay the on-going transaction to P/Lt. Seraspi.

Anent the second requirement, the fact that Macabante, when intercepted by the police, was caught throwing the marijuana stick and when confronted, readily admitted that he bought the same from accused-appellant clearly indicates that Sucro had just sold the marijuana stick to Macabante, and therefore, had just committed an illegal act of which the police officers had personal knowledge, being members of the team which monitored Sucro's nefarious activity.

The court earlier indicated in the case of People v. Bati (G. R. No. 87429, August 27, 1990) that police officers have personal knowledge of the actual commission of the crime when it had earlier conducted surveillance activities of the accused.  Thus, it stated:

"When Luciano and Caraan reached the place where the alleged transaction would take place and while positioned at a street corner, they saw appellant Regalado Bati and Warner Marquez by the side of the street about forty to fifty meters away from them (the public officers).  They saw Marquez giving something to Bati, who, thereafter handed a wrapped object to Marquez who then inserted the object inside the front of his pants in front of his abdomen while Bati, on his part, placed the thing given to him inside his pocket (p. 2)

xxx                   xxx                   xxx

x x x Both Patrolman Luciano and Caraan actually witnessed the same and their testimonies were based on their actual and personal knowledge of the events that took place leading to appellant's arrest.  They may not have been within hearing distance, specially since conversation would expectedly be carried on in hushed tones, but they were certainly near enough to observe the movements of the appellant and the buyer.  Moreover, these prosecution witnesses are all law enforcers and are, therefore, presumed to have regularly performed their duties in the absence of proof to the contrary (People v. Bati, supra citing People v. Agapito, G. R. No. 73786, October 12, 1987)

The accused questions the failure of the police officers to secure a warrant considering that Fulgencio himself knew of Sucro's activities even prior to the former's joining the police force.  Fulgencio reported Sucro's activities only three days before the incident.

As the records reveal, Fulgencio and Sucro had known each other since their childhood years and that after Fulgencio joined the police force, he told the accused-appellant not to sell drugs in their locality.  Hence, it is possible that because of this friendship, Fulgencio hesitated to report his childhood friend and merely advised him not to engage in such activity.  However, because of reliable information given by some informants that selling was going on everyday, he was constrained to report the matter to the Station Commander.

On the other hand, the failure of the police officers to secure a warrant stems from the fact that their knowledge acquired from the surveillance was insufficient to fulfill the requirements for the issuance of a search warrant.  What is paramount is that probable cause existed.  Thus, it has been held in the case of People v. Lo Ho Wing, et al. (G. R. No. 88017, January 21, 1991):

"In the instant case, it was firmly established from the factual findings of the trial court that the authorities had reasonable ground to believe that appellant would attempt to bring in contraband and transport it within the country.  The belief was based on intelligence reports gathered from surveillance activities on the suspected syndicate, of which appellant was touted to be a member.  Aside from this, they were also certain as to the expected date and time of arrival of the accused from China.  But such knowledge was clearly insufficient to enable them to fulfill the requirements for the issuance of a search warrant.  Still and all, the important thing is that there was probable cause to conduct the warrantless search, which must still be present in such a case."

As the Solicitor General has pointed out:

"There are several instances when a warrantless search and seizure can be effected without necessarily being preceded by an arrest provided the same is effected on the basis of probable cause (e. g. stop and search without warrant at checkpoints).  Between warrantless searches and seizures at checkpoints and in the case at bar the latter is more reasonable considering that unlike in the former, it was effected on the basis of probable cause.  Under the circumstances (monitoring of transactions) there existed probable cause for the arresting officers, to arrest appellant who was in fact selling marijuana and to seize the contraband."

That searches and seizures must be supported by a valid warrant is not an absolute rule (Manipon, Jr. v. Sandiganbayan, 143 SCRA 267 [1986]).  Among the exceptions granted by law is a search incidental to a lawful arrest under Sec. 12, Rule 126 of the Rules on Criminal Procedure, which provides that a person lawfully arrested may be searched for dangerous weapons or anything which may be used as proof of the commission of an offense, without a search warrant.  (People v. Castiller, G. R. No. 87783, August 6, 1990)

The accused-appellant claims that the arrest having been done without warrant, it follows that the evidence obtained therefrom is inadmissible.

As earlier discussed, there is nothing unlawful about the arrest considering its compliance with the requirements of a warrantless arrest.  Ergo, the fruits obtained from such lawful arrest are admissible in evidence.

Edison Sucro assails the trial court's reliance on the statement of Macabante whose reason for testifying could be merely to escape prosecution.

We quote the trial court's finding as to the testimony of Macabante:

"The non-filing of a complaint against him for possession of marijuana may have been the reason of (sic) his willingness to testify in court against the accused.  But this does not necessarily taint the evidence that proceeds from his lips.  As explained by Lt. Seraspi, the best sources of information against drug pushers are usually their customers, especially if as in this case, there is no other direct evidence of the selling except the testimony of the buyer.  We accept this observation as a realistic appraisal of a situation in which drug users are, and should be employed by law enforcement authorities to bolster the drive against pushers who are the real felons in our society.  We have observed the demeanor of the witness in court, and found him to be straightforward, unhesitating, and spontaneous in his declarations, so that we are satisfied as to his intention and disposition to tell the truth" (Rollo, p. 40)

Time and again it has been held that the findings of the trial court are entitled to great weight and should not be disturbed on appeal unless it is shown that the trial court had overlooked certain facts of weight and importance, it being acknowledged that the court below, having seen and heard the witnesses during the trial, is in a better position to evaluate their testimonies (People v. Umali, et al., G. R. No. 84450, February 4, 1991 citing People v. Alvarez, 163 SCRA 745 [1988]; People v. Dorado, 30 SCRA 53 [1969]; and People v. Espejo, 36 SCRA 400 [1970]).

Furthermore, the testimony of Macabante was corroborated on material points by public officers Fulgencio and Seraspi.

There is nothing in the record to suggest that the police officers were compelled by any motive than to accomplish their mission to capture a drug pusher in the execution of the crime, the presumption being that police officers perform their duties regularly in the absence of any evidence to the contrary (Rule 131, Sec. 3(m), Revised Rules on Evidence; People v. Castiller, supra citing People v. Natipravat, 145 SCRA 483 [1986]).

The prosecution evidence was further bolstered by the findings of the Forensic Chemist that the items seized were all positive for marijuana.

In contrast to the evidence presented by the prosecution, accused-appellant's defense is alibi which is unavailing considering that he was positively identified by Macabante to be the person from whom he bought marijuana.

Sucro alleges that he could not have committed the crime since he was with his uncle and cousin distributing handbills for his Auntie's candidacy.  The fact, however, remains that it does not preclude the possibility that he was present in the vicinity as established by his admission that he moved a lot and even had the occasion to meet Macabante on the street.

It is well-settled that mere denials cannot prevail against the positive identification of the appellant as the seller of the prohibited substances.  (People v. Khan, 161 SCRA 406 [1988]; and People v. Paco, 170 SCRA 681 [1989])

Premises considered, this Court is convinced that appellant Edison Sucro had indeed committed the offense charged.  The trial court's decision must be upheld.

WHEREFORE, the decision appealed from is hereby AFFIRMED.

SO ORDERED.

Fernan, C.J., (Chairman), Feliciano, Bidin, and Davide, Jr., JJ., concur.