CHIEF JUSTICE MULLARKEY delivered the Opinion of the Court.

In this interlocutory appeal, the prosecution asks us to reverse a trial court order suppressing evidence seized from the defendant Edward Hardrick. While officers were searching a residence and arresting its occupants, the defendant knocked on the door. After inviting the defendant into the residence and identifying themselves as police, the officers asked the defendant to remove his hands from his pockets. The defendant kept one hand in his pocket and then began to turn away from the officers. Fearing that the defendant was reaching for a weapon concealed in his pocket, an officer grabbed the defendant's wrist. After the officer pulled his hand from his pocket, the defendant threw down two baggies of methamphetamine.

CHIEF JUSTICE MULLARKEY delivered the Opinion of the Court.

The trial court granted the defendant's motion to suppress the methamphetamine, holding that the officer lacked the reasonable suspicion necessary to justify grabbing the defendant's wrist. We reverse. We find that the strong government interest in officer and citizen safety justifies a police request that a person show his hands when that person walks into an arrest or search scene. If the person refuses to comply or makes any other furtive gesture, a limited seizure aimed solely at neutralizing any threat to officer or citizen safety is justified.

I. Facts

Around 6:30 p.m. on an August evening, five members of the Grand Valley Joint Drug Task Force went to a residence for a "knock and talk." The officers did not have a search warrant for the address but had linked two men to the address. The men had previously fled from a car in which a pound of suspected methamphetamine and a large quantity of stereo equipment was found. A woman opened the door and a strong smell of marijuana emerged. The officers asked to speak to a resident and identified themselves as police. The woman shut and locked the door. A man, Todd Lee, then opened the door. Again, the officers smelled marijuana. The officers decided to enter the residence and Lee attempted to block the officers' entry. After pushing past Lee, the officers asked him if others were in the house. He told the officers that only two women and some children were there. The officers then found another man who was hiding, two women, several children, marijuana, and suspected methamphetamine. Lee was arrested for obstructing government operations.

A few minutes later, two men arrived at the residence and were admitted. An officer noticed a bulge in one of the men's pockets and patted him down. A marijuana pipe was found.

Shortly thereafter, two more men arrived — the defendant, Edward Hardrick, and his companion, Richard Espino. Espino knocked on the door. An officer opened the door and invited the men to enter the residence. At this point, Hardrick had either one or both of his hands in his pockets. Once the men were inside, two of the officers identified themselves as law enforcement officers. Detective Kramer then ordered Hardrick to remove his hands from his pockets. Hardrick kept one hand in his pocket, clenched in a fist. The trial court notes that Detective Kramer and Hardrick have differing versions as to what happened next. The detective contends that Hardrick turned away from him toward another officer, that he grabbed the wrist of Hardrick's clenched hand, and that Hardrick then pulled his hand out of his pocket and threw two baggies of methamphetamine down an adjacent hallway. Hardrick contends that the detective yanked his hand out of the pocket.

Hardrick was handcuffed and arrested for possession of a schedule II controlled substance and tampering with physical evidence. Hardrick moved to suppress the methamphetamine, contending that its discovery was a result of an illegal search and seizure. Specifically, Hardrick contends that the detective lacked the requisite reasonable suspicion to order Hardrick to remove his hands and to subsequently grab his wrist. The trial court agreed. It held that Hardrick's mere presence in a crime scene does not give rise to reasonable suspicion. It further held that the atmosphere into which Hardrick walked was not a "pervasive dangerous atmosphere" and that Hardrick's "refusal to remove his hand from his pocket contributes nothing towards the existence of reasonable suspicion." We reverse the trial court's suppression of the methamphetamine.

II. Analysis

In reviewing a trial court's suppression order we defer to a trial court's factual findings but review its conclusions of law de novo.People v. Heilman, 2002 Colo. LEXIS 312, *7 (Colo. 2002). Here, we conclude that the trial court's findings of fact are adequately supported by the record. We reject, however, the trial court's legal conclusion that the officer's search of Hardrick was violative of Fourth Amendment principles.

As the United States Supreme Court established in Terry v. Ohio, 392 U.S. 1, 25-26 (1968), an investigatory stop may be employed when an officer has less than probable cause. "Reasonable suspicion" is all that is required to stop and question a suspect or to pat him down in a search for weapons. People v. Smith, 13 P.3d 300, 304 (Colo. 2000). Although the level of suspicion required for an investigative stop or pat-down is less than that needed for an arrest, it still must be judged against the reasonableness standard of the Fourth Amendment. Terry, 392 U.S. at 20. In order to assess reasonableness, a court must identify the government interest allegedly justifying the frisk and balance this against the level of intrusion. Id. at 21.

An officer may conduct an investigatory stop for questioning if (1) there is an articulable and specific basis in fact for suspecting that criminal activity has occurred, is taking place, or is about to occur; (2) the purpose of the intrusion is reasonable; and (3) the scope and character of the intrusion is reasonably related to its purpose. Smith, 13 P.3d at 306.

In this case the second prong — whether the purpose of the intrusion is reasonable — is not at issue. We have repeatedly stressed that a police intrusion based on officer safety concerns is reasonable. See People v. Martinez, 801 P.2d 542, 544 (Colo. 1990);Smith, 13 P.3d at 307; People v. Melgosa, 753 P.2d 221, 225-26 (Colo. 1988); see also Pennsylvania v. Mimms, 434 U.S. 106, 110 (1977) (finding it "too plain for argument" that concern for officer safety is "both legitimate and weighty"). Hardrick contends, however, that the officer lacked reasonable suspicion to stop and frisk him and that the scope of the search exceeded the permissible bounds.

A. The Frisk Was Justified

We first look to whether Hardrick's frisk was justified. To justify a stop, an officer must establish that "specific and articulable facts which, taken together with rational inferences from those facts, reasonably warrant [the] intrusion." Terry, 392 U.S. at 21. It is well established in Colorado that when an officer believes someone may be armed and potentially dangerous, a pat-down search for weapons is appropriate. See, e.g., People v. Jackson, 948 P.2d 506, 507 (Colo. 1997); Martinez, 801 P.2d at 544. In our 1990 decision of Martinez, we approved of a stop in circumstances similar to the ones here.

In Martinez, officers, who were executing a search warrant, found cocaine, handguns, rifles, shotguns, and knives in a Lakewood residence. While the search was in progress, Martinez drove up to the home and walked to the front door. Before Martinez could enter the home, an officer drew his gun and ordered the defendant to stop, raise his hands, and drop to his knees. Martinez began to follow the order but then made a sudden movement with his hand toward his pocket. He was again ordered to raise his hands and was then handcuffed. Id. at 543. This court noted that under the circumstances, the stop was justified:

The record indicates that [the officer] was in the house pursuant to a "no-knock" search warrant and that a substantial amount of drugs and weapons were present. Additionally, he was presented with the scenario of an unidentified person approaching the house. He could not possibly know whether this individual was armed and dangerous without performing a pat-down search. While [the officer] had no reasonable suspicion that the defendant was involved in any crime, we conclude that under the circumstances, with drugs and weapons present in the house, [the officer] was justified in making an investigatory stop of the defendant.

Id. at 544.

Hardrick attempts to distinguish Martinez from the current case. He notes that the officers had already found weapons at the home when Martinez arrived, but here no weapons were found. Hardrick identifies additional differences: although the officers observed Martinez walk up to the residence, Hardrick and his companion knocked on the apartment door; Martinez made a sudden move toward his pocket, but Hardrick already had his hand in his pocket. We find all but the first of Hardrick's proffered distinctions insignificant. Noticing a visitor before he reaches the front door as compared to after he knocks on the door does not provide any more or less certainty as to his purpose there or to the degree of danger. Similarly, refusing to remove a hand from a pocket does not seem any less disconcerting than reaching toward a pocket. Each raises concerns for officer safety.

We do agree, however, that a significant difference between the scenario in Martinez and the one before us is the presence of weapons inMartinez and the absence of weapons here. Certainly, safety concerns are more acute when officers have already found a number of weapons in a home and an unidentified person enters. This difference, however, is not dispositive. All that is required is a reasonable, articulable suspicion that officer safety may be compromised. See Jackson, 948 P.2d at 507-08 (holding that a pat-down search of a passenger is justified when an officer stops a car for a traffic infraction and a passenger in that car makes the furtive gesture of pulling his coat from the back seat of the car onto his lap).

We find that the circumstances of this case, taken as a whole, justify the officer's stop of Hardrick. First, although no weapons were found at the scene, drugs were found, thus increasing the risk of violence. See Michigan v. Summers, 452 U.S. 692, 702-703 (1981) (noting that "the execution of a warrant to search for narcotics is the kind of transaction that may give rise to sudden violence or frantic efforts to conceal or destroy evidence. The risk of harm to both the police and the occupants is minimized if the officers routinely exercise unquestioned command of the situation"). Second, the occupants of the house were not cooperative. This is a significant factor in determining the danger of an unknown, possible compatriot appearing on the scene. Third, Hardrick did not comply with the officer's attempts to ensure that he was not a safety threat. The trial court found that he refused to comply with the officer's requests for him to remove his hands from his pockets. Under these circumstances, a limited stop was justified. "The officer need not be absolutely certain that the individual is armed; the issue is whether a reasonably prudent man in the circumstances would be warranted in the belief that his safety or that of others was in danger." Terry, 392 U.S. at 27.

When there is an ongoing search or arrest and a third party voluntarily arrives at the scene, it is unreasonable to ask an officer to simply send the interloper away from the immediate area and hope that he is not setting himself up for an ambush. It is equally unreasonable for the officer to allow the third party into the volatile situation without insuring that the party is not armed. See Smith, 13 P.3d at 307 (holding that when a second car pulled up and stopped behind a police officer presently engaged in the traffic stop of a stolen car, the officer reasonably stopped and searched the second car to secure his own safety). The stop here was appropriate, and is quite distinguishable from a situation where an innocent passerby inadvertently happens onto a crime scene in public open space or where the police actively follow and approach an individual on a public street. See Outlaw v. People, 17 P.3d 150, 153-54 (Colo. 2001) (finding that the police lacked reasonable suspicion to stop a man who was walking down a public street with his hand closed in a fist).

B. The Scope of the Intrusion Was Proper

Hardrick also argues that even if the stop was justified, the scope of the frisk in this case was unreasonable. We disagree. As mentioned above, in order to comport with the federal and Colorado search and seizure provisions, not only must a stop be justified, but the scope of the intrusion must be reasonable. In the current case, Hardrick refused to remove his hand from his pocket. This, coupled with the other facts of this case, provided sufficient justification for the officer to respond by grabbing Hardrick's wrist to prevent Hardrick from using a weapon concealed in his pocket. The trial court did not determine whether the officer pulled Hardrick's hand out or whether Hardrick did so. We find that even if the officer pulled his hand out, the officer's actions were justified by the circumstances.

As the United States Supreme Court has noted, "[t]he calculus of reasonableness must embody allowance for the fact that police officers are often forced to make split-second judgments — in circumstances that are tense, uncertain, and rapidly evolving — about the amount of force that is necessary in a particular situation." Graham v. Connor, 490 U.S. 386, 396-97 (1989). In the current case, the officers were confronted with a stressful arrest and search situation in which the occupants of the house had already lied to the police and where the officers had already found drugs, encountered resistance, and discovered a suspect hiding in a small utility room. When a man with his hands in his pockets entered the scene and would not comply with officer orders to show his hands, it was reasonable for the officer to grab Hardrick's hand. Accord Martinez, 801 P.2d at 544-45 (finding that officer safety concerns justify ordering a suspect at gun point to drop to his knees and subsequently handcuffing him); Reyes v. U.S., 758 A.2d 35, 38-39 (D.C. 2000) (holding that, when the defendant refused repeated requests to remove his hand from his pocket, officer safety concerns justified grabbing the defendant, pulling him over to the police cruiser and forcing him to remove his hand from his pocket and open his hand).

Moreover, the scope of this search did not exceed that necessary to ensure officer safety. When a search is justified by officer safety concerns, it must be limited to a search for weapons, and cannot be expanded to look for evidence. See Terry, 392 U.S. at 29; Martinez, 801 P.2d at 544. Accordingly, in Martinez, when a search that was justified by a legitimate concern for officer safety ended with an officer opening a small pouch filled with amphetamine, we held that the search had exceeded a reasonable scope because "no reasonable person could believe that the pouch was a weapon or that it contained a weapon." Id. at 545. The current case is not one in which an officer uses the pretext of a weapons search to search for other evidence. Rather, he simply asked Hardrick to show his hands and when Hardrick refused to do so, grabbed his hand for his own safety. Once Hardrick threw packets of drugs down the hallway, they were then in plain view and the officers appropriately seized them. See Melgosa, 753 P.2d at 226.

In sum, we conclude that any time an officer is engaged in a valid search or arrest and a third party inserts himself into the situation, the officer may ask the interloper to show his hands. If the individual refuses to do so, or makes any other furtive gesture, such conduct raises a reasonable suspicion that officer safety and the safety of others may be compromised. Accordingly, it is consistent with the Fourth Amendment and Article 2, Section 7 of the Colorado Constitution to briefly detain the suspect in order to defuse any danger.

The trial court's suppression order is reversed, and the case remanded.