On August 3, 2007, a three-count criminal complaint was issued by the Chelsea Division of the District Court Department, charging the defendant, Vladimir Samuel, with possession of a firearm without a firearm identification card, carrying a firearm without a license, and carrying a loaded firearm without a license.

*561On February 28, 2009, the defendant filed a motion to suppress the firearm that had been seized on the ground that the police had conducted a warrantless search. Following a hearing, a District Court judge allowed the suppression motion. The Commonwealth’s motion for reconsideration was denied, and a single justice of the Supreme Judicial Court granted the Commonwealth’s application for interlocutory review of the District Court judge’s order pursuant to Mass.R.Crim.P. 15(a)(2), as appearing in 422 Mass. 1501 (1996).

We summarize the judge’s findings of fact, supplemented with uncontested testimony adduced at the evidentiary hearing. Commonwealth v. Isaiah I., 448 Mass. 334, 337 (2007).1

On August 2, 2007, at 11:45 p.m., Officer Edwin Hernandez of the Chelsea police department was working at the front desk when he received a telephone call from a Spanish-speaking man. The caller identified himself to Officer Hernandez and stated that he was at 262 Maple Street, apartment 1, in Chelsea.2 He stated that there were persons in a room with him, including a black male sitting on a couch. That individual had displayed a handgun, showed it was loaded, and told the caller and others in the room that he had been hired to kill someone. He then placed the firearm under a pillow on the couch where he was sitting. The caller told Officer Hernandez that he was afraid for his safety. Officer Hernandez dispatched several Chelsea police officers to the address given by the caller and told them that the caller was in the apartment with the suspect. They knocked on the apartment door, and a resident of the apartment responded.3 The police asked the resident if they could enter the apartment in order to conduct a well-being check of the parties in the apartment. The resident gave the police permission to do so. The officers went directly to the back room of the apartment where they *562had been told the black male identified by the caller would be sitting. In the back room, the officers discovered various males sitting in several locations around the room. As described, the police saw a black male sitting on a couch with a pillow next to him. An officer ordered the individual to stand up and move to one side away from the pillow. The officer picked up the pillow and saw a handgun under it. The handgun was seized, and the defendant was arrested.

At the hearing on his motion, the defendant argued that because the search of the apartment exceeded the consent given for the officers’ entry, the seizure of the firearm was improper. The Commonwealth responded that the circumstances constituted an exigency, and therefore the police seizure of the firearm was proper.

Based on his findings of fact, the judge concluded that the entry of the police into the apartment was proper because the resident had consented to their entry. The judge ruled, however, that once the police were in the apartment, their subsequent conduct in lifting the pillow and removing the firearm constituted an improper search because it exceeded the scope of the consent. The judge dismissed the exigency argument, citing Commonwealth v. Alvarado, 423 Mass. 266, 273 (1996), and noting that no court decision has held that reasonable suspicion arises “simply on a report of gun possession.”4

On appeal, the Commonwealth claims, among other things, that the nature of the circumstances created an emergency that justified the seizure of the firearm and the arrest of the defendant.5 The defendant counters that the motion judge correctly concluded that the seizure of the firearm was improper.

Discussion. Our courts have held that “ ‘[t]he need to protect *563or preserve life or avoid serious injury is justification for what would be otherwise illegal, absent an exigency or emergency.’ ... In justifying action under this doctrine, the Commonwealth has the burden of showing . . . that ‘the authorities had a reasonable ground to believe that an emergency existed, and . . . [that] the actions were reasonable under the circumstances.’ ” Commonwealth v. DiMarzio, 52 Mass. App. Ct. 746, 750 (2001), S.C., 436 Mass. 1012 (2002), quoting from Commonwealth v. Morrison, 429 Mass. 511, 514-515 (1999). See Brigham City v. Stuart, 547 U.S. 398, 403 (2006). See also Commonwealth v. Lindsey, 72 Mass. App. Ct. 485, 488 (2008), cert. denied, 556 U.S. 1183 (2009).

Here, the police received information from an identified citizen that an individual at a named location had displayed a loaded firearm to persons in a room, had announced that he was hired to kill someone, and had placed the firearm under the pillow next to him. The caller reported that he became frightened.

As a result of the information, the police had reasonable grounds to believe that an emergency existed and that lives were in danger. We agree with the motion judge (and the defendant) that the police entry into the apartment was justified. Once inside the apartment, the emergency did not abate because it was necessary to remove the firearm in order to protect life and to prevent injury to others. Upon entering the back room, the police corroborated the information given by the identified caller to Officer Hernandez, including the seating of the black male on the couch with a pillow beside him. At that point, the officers had reasonable suspicion, if not probable cause, to believe that a loaded firearm was under the pillow, a firearm that was to be used to kill someone.

The Commonwealth contends that the conduct of the police in lifting the pillow and seizing the firearm was reasonable. We *564agree and note that “ [reasonableness must be ‘evaluated in relation to the scene as it could appear to the officers at the time, not as it may seen to a scholar after the event with the benefit of leisured retrospective analysis.’ ” Commonwealth v. McDermott, 448 Mass. 750, 766, cert. denied, 552 U.S. 910 (2007), quoting from Commonwealth v. Young, 382 Mass. 448, 456 (1981). “The role of a peace officer includes preventing violence and restoring order . . . .” Brigham City v. Stuart, supra at 406. We hold that the action of the police in seizing the firearm was reasonable under the circumstances.

Accordingly, we reverse the order allowing the motion to suppress, and the matter is remanded to the District Court for further proceedings consistent with this opinion.

So ordered.