Defendant appeals his conviction under ORS 475.9921 for possession of a controlled substance. He assigns as error the trial court’s denial of his motion to suppress evidence gathered during a search of his residence and the surrounding premises.2
During the hearing on defendant’s motion to suppress, the state called two principal witnesses, officers Klejmont and Sharp of the Portland Police Bureau, Special Investigation Division, who testified that they had approximately six or seven months’ experience in narcotic investigations. Klejmont testified that the investigation of defendant was prompted by information received about September 1, 1980, from a confidential informant.
Sharp testified that the informant had provided substantial information relating to trafficking in narcotics and dangerous drugs, which he or Officer Klejmont checked and found to be accurate; at the direction of Sharp, the informant had purchased controlled substances, which were determined to be what they purported to be after testing; he had, in the past, furnished Sharp or Klejmont with information which had led to the issuance of at least one search warrant leading to the seizure of controlled substances, an arrest and a criminal charge.
Given that kind of relationship with the confidential informant, the officers had good reason to believe that he was reliable3 at the time he gave them the information involved in this case. The officers, therefore, were entitled to believe what the informant had told them: he had personally observed a *214man whom he knew, Kevin, and Kevin’s brother make telephone calls on several occasions to a person named Jim, following which a person named Jim delivered marijuana in large quantities, from 10 to 30 pounds, to Kevin or his brother. The informant had been told, but did not know of his own knowledge, that Jim had 1,000 pounds of marijuana and kept it in an outbuilding on the premises. Kevin had also told him the location of Jim’s premises in Sandy and had described them to him; he gave that information to the officers. Although the informant had not been to Jim’s premises, he took the officers there using the information he had obtained from Kevin. The premises were as described by the informant, including the existence of guard dogs and an outbuilding. When the informant took the officers to Jim’s place, he saw Kevin’s brother on the premises, causing the informant to become excited and to duck down in the car in order not to be seen. Subsequently, the officers determined that the premises were owned by defendant and that an automobile in the driveway was registered to him.
During the ensuing two or three weeks, the officers conducted periodic surveillance of the premises for one to three hours at a time, approximately seven times during that period. On the basis of the information obtained from the informant, the officers had a well-founded suspicion that Jim was supplying substantial quantities of marijuana to Kevin and his brother, that Jim was conducting a relatively large scale operation and that Jim lived on the premises described by the informant, who took them there. Surveillance of the premises, however, over the two or three week period did not reveal any suspicious activity until September 24.
On that date, the officers observed six or seven vehicles pull into defendant’s driveway, stay for five or ten minutes and then leave. They could not see what was going on until one of the officers, from a lawful vantage point in a tree in defendant’s neighbor’s yard,4 observed activity that reasonably appeared to be the transfer of large quantities of marijuana. Klejmont saw defendant and another man, later identified as Chris Burnett, moving rapidly from behind defendant’s house, where the barn was located; each was carrying two white plastic garbage bags in each hand. They *215moved toward Burnett’s automobile and defendant’s camper, returned empty-handed and then repeated that process until approximately 20 bags had been moved in that manner. They also heard a whining noise coming from the barn, which sounded to them like a dryer that might be used to dry marijuana for use.
At that point, the officers concluded, we think correctly, that the information they had received from the informant, coupled with their observations, was sufficient to give them probable cause to search the premises. The hearsay information that defendant had 1000 pounds of marijuana on his premises, on which the officers had no basis to rely earlier, attained a ring of veracity when they observed defendant’s activities on September 24. Further, even if the information obtained by the officers from the informant, taken by itself, was stale, see State v. Scheer, 49 Or App 937, 620 P2d 973 (1980), it was supplemented and updated by the officers’ observations on September 24. Sharp made some telephone calls to the Clackamas County sheriffs office requesting assistance and gave them the address and directions on how to get there. After some confusion, explained below, Klejmont and Sharp rendezvoused with a deputy sheriff from Clackamas County, and all three of them entered the property to “freeze the scene” until they could get a warrant.
The question remains whether the circumstances at that time were such that the officers reasonably believed that, if they did not enter the premises promptly, the evidence would be lost. Under all of the circumstances, we conclude that there were exigent circumstances authorizing immediate entry to search for and seize marijuana. Klejmont had just observed defendant and Burnett hurrying back and forth between the barn and the vehicles carrying large plastic bags that he could have reasonably believed contained marijuana, the subject of the investigation. From that observation, he could have reasonably believed that the men were in the process of removing the evidence from the premises. The officers did not know how many persons were on defendant’s premises and reasonably considered it advisable to obtain the assistance of additional officers.
When the deputy sheriff responded to Sharp’s call for help, he sped by the officers’ station near defendant’s property *216with his overhead lights on in a marked police vehicle. Sharp’s vehicle was parked in a neighboring driveway; he jumped in his car and pulled out to give chase to the deputy who had passed by as Klejmont ran to, and jumped into, the car with Sharp. As that occurred, the deputy who had passed them made a quick U-turn and came back to defendant’s driveway.
The officers’ observations, plus all of the commotion and obvious police presence at that time,5 reasonably indicated that there was a significant risk that the persons on defendant’s premises either already were or would have been alerted to the fact that the police were present and that they would attempt to get rid of the evidence and disappear. Defendant contends that they could have waited outside while they attempted to obtain a search warrant, and if anyone had attempted to drive away they could have stopped him. However, to engage in that kind of second-guessing in a situation that reasonably could have appeared to require immediate action seems inappropriate. Given some of the language in State v. Hansen, 295 Or 78, 664 P2d 1095 (1984),6 it is at least questionable whether keeping the premises under siege from outside the property line would have been preferable from a constitutional standpoint. Accordingly, we conclude that the trial court’s conclusion that there were exigent circumstances is supported by the record.
Given the existence of probable cause and exigent circumstances, the officers were entitled to enter defendant’s *217premises for the purpose of searching for and seizing marijuana. The fact that they stated that their purpose was to “freeze the scene” until they obtained a warrant does not affect the lawfulness of their entry. When they entered the premises, defendant fled and Sharp pursued him unsuccessfully. During the pursuit, he entered the barn, where he observed four plastic bags and some fans. In the meantime, Klejmont apprehended Burnett, who had not attempted to flee. When Sharp returned from his abortive attempt to apprehend defendant, he, Klejmont and Burnett went through defendant’s residence to see if other persons were present who might threaten their safety. They saw in plain view a “bong” on the kitchen table.
Following the “protective sweep,”7 they went outside, advised Burnett of his rights and sought and obtained his permission to search his automobile. They found several bags of marijuana, which Burnett said defendant had told him to put there. Later, other officers arrived and “secured the area,” and no further search occurred until a warrant was obtained.
Given our conclusion that there was a lawful entry by the officers onto defendant’s property, their “freezing the scene” does not invalidate their immediate limited search of defendant’s premises or the consent search of Burnett’s automobile. Because that evidence, without regard to evidence seized pursuant to the warrant, was sufficient to convict defendant of possession of marijuana, it is not necessary to decide what effect, if any, the “freeze of the scene” had on the subsequent search pursuant to the warrant. See State v. Hansen, supra. The admission of that evidence, which was cumulative only, was harmless beyond a reasonable doubt. Chapman v. California, 386 US 18, 87 S Ct 824, 17 L Ed 2d 705 (1967).
Affirmed.
ORS 475.992 prohibits the manufacture, delivery and possession of a controlled substance.
Although search and seizure issues are usually raised in the context of the United States Constitution, Amend IV, or Oregon Constitution, Article I, section 9, neither defendant’s brief nor the state’s directs our attention to either of those constitutional provisions. We, therefore, do not know whether defendant is relying on state or federal constitutional principles.
It should be noted that defendant does not question the reliability of the confidential informant or the reasonableness of the officers’ belief that he was reliable. He does question the basis for the informant’s knowledge communicated to the officers, and also asserts the staleness of that information.
The officers obtained permission from the neighbor.
Concededly, officers may not create their own exigent circumstances in order to bypass the warrant requirement. State v. Fondren, 285 Or 361, 591 P2d 1374 (1979). Here, however, the commotion was not instigated by Sharp and Klejmont, who were the only officers on the scene and were the ones who made the decision that immediate action was necessary. Unless it can be said that Sharp’s failure to tell the deputy sheriff to turn off his flashers when he approached the scene was the cause, there is no reason to hold, as the dissenting opinion of Warren, J., would, that the exigent circumstances were created by the responsible officers. In any event, their earlier conclusion that the persons present on defendant’s premises might have been alerted to the police presence was reasonable.
In Hansen, the court said: “Quite simply, what the police officers did in ‘securing’ the residence was to seize it in the constitutional sense.” 295 Or at 84. There, however, although the officers had probable cause to believe the defendant had committed a crime, there were no exigent circumstances to justify the entry of the defendant’s residence. Accordingly, that case holds, the police were trespassers, and when they “secured” the premises they “as effectively reduced the marijuana to the control of the trespassing police as if they had actually discovered and taken physical possession of it. * * *” 295 Or at 97. The marijuana seized pursuant to a subsequently obtained warrant was held to be suppressible.
Given our conclusion, it is not necessary to decide the validity of that police action.