The precise point at which an encounter between the police and the public “constitutes an intrusion of constitutional dimensions requiring justification,” Commonwealth v. Stoute, 422 Mass. 782, 789 (1996), continues to challenge courts, law enforcement officials, and defense counsel as the factual circumstances underlying cases raised on appeal remain as varied as human conduct itself. Here, the Commonwealth appeals the allowance of the defendant’s motion to suppress physical evidence, a firearm, discarded by the running defendant under conditions which we recount in full.
Factual background. Following a hearing on the motion to *478suppress, the judge found as follows. During a conversation between Boston police Officers Cogavin, Cooley, and Tarrantino1 and four males known to the officers for gun-related incidents, Cooley saw one of the males look at the defendant (who was nearby on a bicycle), “make some sort of hand gesture to [the defendant] and then walk away from [the defendant], the three other males and the police. Cooley saw [the defendant] turn around and [pedal] his bike away from the four males and [the] three plain-clothed police officers.”
“The three police officers entered their unmarked police car without [activating] lights or a siren and followed [the defendant], who was riding his bike. The driver pulled the unmarked cruiser beside [the defendant] and Cooley said[,] ‘What’s up, can we talk to you?’ [The defendant] had a panicked look. The officers had no information from any source supporting a conclusion that [the defendant] had committed a crime, was committing a crime or was about to commit a crime.” The defendant sped up and pedaled ahead of the cruiser. He then “dropped his bike and started to run. The officers jumped out of the cruiser and ran after him.” As he ran after the defendant, Tarrantino “saw [the defendant] pulling at his waist band and then saw what looked like the handle of a gun. Tarrantino called out to his partners[,] ‘He’s got a gun,’ and continued running after [the defendant]. He saw [the defendant] throw the gun onto a roof. Cooley caught [the defendant], took him to the ground at which point he was handcuffed. A gun was found on the roof where [the defendant] had thrown it.”2
Discussion. The judge’s order assumes that the police had no justification to stop the defendant at the time he discarded his firearm. The Commonwealth asserts as alternative grounds for error that no seizure had occurred at the time the defendant *479discarded his gun in public or that, if a seizure occurred, it was justified. We conclude that this case is governed by the recent Supreme Judicial Court decision in Commonwealth v. Sykes, 449 Mass. 308 (2007), and, accordingly, reverse the suppression of the firearm. Here, as in Sykes, no stop in the constitutional sense occurred before the defendant abandoned his bicycle and began to run. By that time the police possessed a reasonable suspicion of criminal activity sufficient to justify a stop.
It is difficult to distinguish Sykes in any material respect from the sparse record here presented on appeal. The facts in Sykes are as follows: there, the defendant, on a bicycle, observed plain-clothed police officers, pedaled away with some backward looks at the officers, increased his speed to pull ahead of the unmarked cruiser when the police pulled alongside and asked to talk with him, collided with a tree, abandoned his bicycle, began running while “clenching his waistband,” was followed by police officers on foot, and threw away his gun during the pursuit while under police observation. Id. at 309-310. The factors selected by the dissent to distinguish Sykes from the instant case do not appear to create a material difference. Specifically, the officers’ response in Sykes to a 911 call regarding alleged drug activity in a high crime area is the functional equivalent in this case of the officers’ questioning of four individuals known for criminal activity involving firearms. The defendant’s “panicked look” in this case is somewhat more suggestive than the unspecified backward looks the defendant in Sykes made to the officers behind him. The defendant in Sykes “clench[ed] his waistband” earlier in the chain of events than the defendant in this case was observed “pulling at his waist band”; that does not constitute a distinction of legal import in determining whether either defendant had demonstrated behavior sufficient to justify a threshold inquiry. In both cases, “[t]he fact that the defendant chose to abandon his bicycle in an effort to dodge further contact with the police was significant.” Id. at 315. We also note additional factors, not present in Sykes, that justified the police in considering the defendant’s behavior in this case to be suspicious, namely, his movement away from the group after receiving a hand gesture from one of the males known to the police for gun-related incidents, and the fact that his abandonment of his bicycle was wholly *480intentional, rather than precipitated by an accident. As in Sykes, by the time the defendant abandoned his bicycle, the police possessed reasonable suspicion of criminal activity sufficient to justify a stop.
As the United States Supreme Court has noted, “nervous evasive behavior is a pertinent factor in determining reasonable suspicion.” Illinois v. Wardlow, 528 U.S. 119, 124 (2000). See Commonwealth v. Sanchez, 403 Mass. 640, 645-646 (1988) (“the defendant broke away from the police before they pursued him, thus providing the police with a reasonable and articulable suspicion”); Commonwealth v. Sweezey, 50 Mass. App. Ct. 48, 52 (2000) (defendant’s flight after valid stop by officers elevated officers’ reasonable suspicion of criminal activity); Commonwealth v. Wilson, 52 Mass. App. Ct. 411, 415 (2001), quoting from Commonwealth v. Marrero, 33 Mass. App. Ct. 440, 443 (1992) (flight a relevant factor where it has not been triggered by inappropriate police action).3
In the instant case, the defendant’s flight was not preceded “by any inappropriate police action,” Commonwealth v. Marrero, supra at 443, and it occurred before any “inquiry of the defendant . . . or pursuit of him personally was attempted.” Commonwealth v. Wilson, supra at 415. “The flight could therefore be considered in determining whether reasonable suspicion existed when the police began to chase the defendant.” Ibid. Accordingly, “[w]e conclude that all of the defendant’s actions, taken together, were sufficient to give rise to reasonable suspicion of criminal activity.” Commonwealth v. Sykes, 449 Mass. at 315.
The order allowing the defendant’s motion to suppress physical evidence seized and any statements made by the defendant is reversed, and the case is remanded for further proceedings.
So ordered.
We note that Officer Tarrantino’s name is also spelled “Tarantino” in the judge’s memorandum of decision. Without knowing which version is correct, we use “Tarrantino” throughout this opinion.
The judge specifically found all other testimony “not credited.” The Commonwealth failed to include any transcripts or other evidence in the record on appeal; we therefore do not consider any possible challenge to the adequacy of evidence to support the judge’s findings, and note that the failure to provide a transcript makes more difficult the type of fully comprehensive overview on which appellate review is properly based.
We find the dissent’s conjecture that the defendant was unaware of the presence of any police when he commenced his evasive behavior to be unpersuasive; in any event, the defendant’s state of mind is not relevant to whether his conduct, viewed objectively by the police, gave rise to reasonable suspicion.