Appellant was convicted of two counts of armed robbery, D.C.Code §§ 22-2901, -3202 (1989), and one count of possession of a firearm during a crime of violence or dangerous offense, D.C.Code § 22-3204(b) (1989). Appellant argues on appeal that certain tangible evidence, including an imitation Uzi machine gun, should have been suppressed because it was seized during a search that violated the District of Columbia’s “knock and announce” statute, D.C.Code § 23-524(a) (1989).1 In denying appellant’s motion to suppress, the trial judge found that the police action was justified by exigent circumstances. We affirm.
I.
On November 26, 1990, at approximately 8:00 p.m., a man entered the Trak Auto store located at 318 Riggs Road, N.E., wearing a mask and carrying a Tropicana juice box. He walked to the parts counter, pulled an Uzi style machine gun2 out of the box and ordered the store manager, who was servicing a customer, to open the store safe. After the manager gave the gunman $508 from the safe, another store employee was ordered to turn over $338 cash from the cash register. The assailant then backed out of the store holding the employee, as a human shield, at gunpoint. As he reached the door the gunman took off his mask, pushed the employee away, and fled the store.
Store employees identified the appellant as the gunman from a photo array. It was then ascertained that the appellant resided at 611 Keefer Place, N.W. In addition, the police learned from an informant, who had personally observed the weapon, that the Uzi was present inside of the premises within the 24 hours preceding the search warrant application and that appellant had spoken of “doing a robbery.” Finally, appellant fit the description of the perpetrator of approximately eleven other robberies, all within the six weeks preceding the search, involving the use of an automatic weapon similar to the one used in the Trak Auto robbery.3 Based-on this information, the police requested a search warrant for the Keefer Place premises. Because of the nature of the weapon, and its repeated recent use by appellant, a nighttime warrant was sought and approved by the authorizing judge, because it was believed that, under the circumstances, a search at night would be less dangerous.
The Special Operations Division’s Emergency Response Team (“ERT”) was requested to execute the warrant based on the potential for violence. When the ERT arrived at the appellant’s residence at 8:00 p.m. on December 4, 1990, approximately eight days after the Trak Auto robbery, they saw lights and heard voices coming from inside the home. Officer Grooms *462knocked on the door three times with his shield and announced, “Police, search warrant.” The talking stopped and thereafter there was no acknowledgement of the knock, sound of movement toward the door, or scuffling inside the home. After five seconds the police used a battering ram to force open the door. The police waited only five seconds because they feared that “any other delay would have possibly allowed someone inside to arm themself with this weapon.” The officers arrested the appellant and discovered an imitation Uzi machine gun in the rafters of the basement ceiling where the informant had reported seeing it.4
Prior to trial, appellant, moving to suppress tangible evidence seized from the house in which he was arrested, challenged the search on three separate grounds: (1) that the search warrant was not supported by probable cause, (2) that the warrant was executed at nighttime but did not comply with the requirements of a nighttime search warrant, and (3) that the officers violated the knock and announce requirements of the D.C.Code. The motions judge rejected each claim and denied the motion. The judge found that exigent circumstances justified the forced entry after the passage of only five seconds because the nature of the weapon posed “a serious risk of injury to the police or other citizens. ...”
On appeal, the only claim presented is that the motions judge erred in concluding that the officers’ entrance did not violate the knock and announce requirements.
II.
It is well established that the “police may not forcibly enter a person’s house without prior announcement.” Williams v. United States, 576 A.2d 700, 703 (D.C.1990) (citing Miller v. United States, 357 U.S. 301, 306-08, 78 S.Ct. 1190, 1194-95, 2 L.Ed.2d 1332 (1958) (“From the earliest days, the common law drastically limited the authority of law officers to break the door of a house to effect an arrest.”)). When executing a search warrant at a residence, the police must knock and notify the occupants of the police authority to search the home, D.C.Code § 23-524(a) (incorporating 18 U.S.C. § 3109). This court’s interpretation of the knock and announce provision in § 33-565(g), which is virtually identical to its federal counterpart, 18 U.S.C. § 3109, and federal circuit courts interpreting that provision, have recognized two broad exceptions to the knock and announce requirement. The first exception allows police to enter without delay if the police can reasonably infer from the actions or inactions of the occupants that they have been refused admittance.5 United States v. Covington, 385 A.2d 164, 168 (D.C.1978). The second exception allows police to enter if they are confronted with exigent circumstances, such as the imminent destruction of evidence or danger to the entering officer. Williams v. United States, supra, 576 A.2d at 703.
Our review of appellant’s challenge to the trial court’s determination that exigent circumstances justified the police intrusion must afford the government “all legitimate inferences from the testimony and uncon-troverted facts of record,” United States v. Covington, supra, 385 A.2d at 166 (quoting Jenkins v. United States, 284 A.2d 460, 462 (D.C.1971)), if those inferences are *463“supportable under any reasonable view of the evidence.” Ibid, (quoting Scarbeck v. United States, 115 U.S.App.D.C. 135. 155, 317 F.2d 546, 562, cert. denied, 374 U.S. 856, 83 S.Ct. 1897, 10 L.Ed.2d 1077 (1963)).
In the present case, the issue before the motions judge in determining exigency was whether the evidence satisfied an “objective test ... which calls for a ... judicial evaluation whether those circumstances support a legal conclusion of ... exigent circumstances_” United States v. Bonner, 277 U.S.App.D.C. 271, 278, 874 F.2d 822, 829 (1989). The test is how a reasonable and experienced officer would respond under these circumstances. See Williams v. United States, supra, 576 A.2d at 704 (citing United States v. Bonner, 277 U.S.App.D.C. at 278, 874 F.2d at 829). Applying these principles, the trial judge found that:
these officers were acting reasonably] in concluding after a very short passage of time that there was an exigent need to enter those premises by force immediate[ly] in order to avoid ... what was believed to be a serious risk of injury to the police or other citizens in the execution of that warrant.
The trial judge noted five factors that taken together justified the officers’ determination that exigent circumstances necessitated their forced entry. First, the police were executing a warrant that had grown out of an investigation for at least twelve armed robberies in which the perpetrator used a weapon described as an Uzi type machine gun. Appellant had been linked to all of those robberies by identification evidence of one kind or another. Second, the information that the appellant was using drugs increased police concern about executing the warrant. Third, the ERT had reviewed the application and “made its own independent judgment that it was an appropriate warrant for them to execute because of the danger to citizens and law enforcement personnel ... reasonably posed by appellant in those premises and the weapons accessible to him.” Fourth, if appellant believed the police were there for him, he might act in a desperate way to avoid apprehension and use the weapon that was at his disposal or the weapon police believed was at his disposal. Fifth, and according to the trial court the most significant reason, “this wasn’t just any kind of weapon, it was an automatic or at least semiautomatic machine gun type weapon which was capable of inflicting tremendous damage in a very short period of time before the officers could adequately defend themselves.” The trial judge concluded that there was danger to the officers, stating:
while there is not the kind of scurrying through the house which the officers could conclude was an attempt to destroy evidence or obtain weapons that other cases have pointed to as exigent circumstances justifying an immediate entry, for all the police knew Mr. Culp didn’t have to scurry anywhere to get his Uzi weapon because it was immediately available to him....
We have recognized that the purpose of the knock and announce statute is to protect and encourage police safety. Williams v. United States, supra, 576 A.2d at 706. In Williams, however, we also recognized that there are circumstances “where the police officers’ safety is better protected by immediate forced entry, than by rigid adherence to the knock and announce requirement.” Id. Our review of the record persuades us that the trial judge did not err in concluding that exigent circumstances justified the police action taken here.
It is clear from the record that when the ERT arrived at appellant’s residence they knew that he was suspected of committing as many as twelve robberies, each using an Uzi type weapon. They also knew that appellant had used the weapon to take a human shield to ensure safe escape after committing the latest robbery and in one previous robbery had “racked the action,” i.e., moved bolts on top of the gun in a threatening manner. The ERT had also learned, from a person who had seen the weapon, that the Uzi had been seen on the Keefer Street premises within the past twenty-four hours and appellant *464spoke of “doing a robbery.”6 Moreover, they were aware that appellant had a record for violence and PCP use, and they had been informed that appellant was using drugs at the time. See Coates v. United States, 558 A.2d 1148, 1151 (D.C.1989) (“[PCP] users may act in a very violent and irrational way following use of the drug”). When the ERT arrived at the premises, they saw lights and heard voices inside the home. Their knock and announcement of their authority and purpose was met with silence.7 The motions judge found that the police were reasonable in concluding that there was serious risk of injury in any further delay. We agree and hold that the trial judge’s conclusion was supported by ample evidence and find no basis for disturbing it. See Covington, supra, 385 A.2d at 166.
For the reasons stated, we find that the police action was warranted under these circumstances and the trial court properly denied the appellant’s motion to suppress the evidence.
Accordingly, the judgment is
Affirmed.
.In their briefs, both appellant and the government relied on the "knock and announce” provision set forth in D.C.Code § 33-565(g) (1988). That provision, however, is only applicable to search warrants for controlled substances. The statute which governs the search in question here, D.C.Code § 23-524, incorporates section 3109 of title 18 of the United States Code which provides:
The officer may break open any outer or inner door or window of a house, or any part of a house, or anything therein, to execute a search warrant, if, after notice of his authority and purpose, he is refused admittance or when necessary to liberate himself or a person aiding him in the execution of the warrant.
18 U.S.C. § 3109 (1991). This language is nearly identical to that of D.C.Code § 33-565(g), which differs only in that it does not include the language after the word "admittance."
. According to a police witness, an Uzi machine gun carries "at least 32 rounds of ammunition ... which [are] fired ... at rapid velocity” (sic).
. The police documented the similarities in the descriptions of the perpetrator(s) of all twelve crimes in a "flow chart” attached to the affidavit in support of the nighttime search warrant. Our own examination of these descriptions persuades us that the police had reasonable grounds for suspecting that appellant had committed all or most of them.
. Although the gun was a plastic imitation of an Uzi submachine gun, Detective Steven Mann testified that visually it was identical to a real weapon. Mann testified that the only difference is that a real gun is heavier. We agree with the trial judge who observed:
Just as it is inappropriate to use things that were discovered after the search to justify the basis for the search in the first place, it is also inappropriate to use things that were discovered after the search to invalidate a search that was otherwise proper at its inception. And, therefore, it is not proper for a reviewing court to consider the fact that the Uzi turned out to be a toy gun or that the people in the premises were not, in fact, armed with any weapons when they finally got inside.
. The trial judge also found that the entry after only a five second delay was supported by the constructive refusal of the occupants to open the door. Since we hold that the entry was supported by exigent circumstances, we do not address the constructive refusal finding by the trial judge.
. The search warrant was executed eight days after the Trak Auto robbery in which the assailant had used an automatic weapon. We do not believe that this lapse of time diminishes the exigency since the police had very fresh information that the Uzi was seen on the premises.
. Nor is it without significance that the police indisputably knocked and announced their authority and purpose, meeting one of the requirements of 18 U.S.C. § 3109. In United States v. Bonner, supra, in which the police had similarly announced their authority and purpose, and the issue was whether exigent circumstances justified their hasty entry, the court explained:
Whether the exigency is sufficient to justify the officers’ challenged behavior turns upon the extent and nature of the departure that must be justified. The exigency required to justify a warrantless search differs from that required to excuse noncompliance with section 3109’s announcement provision. That degree of exigency is, in turn, greater than that needed to excuse noncompliance with only the refusal portion of section 3109.
277 U.S.App.D.C. at 275, 874 F.2d at 826 (emphasis added). At least where a crime of violence is the subject of the search warrant, as here, we agree that the extent of departure from the statute’s commands is relevant to the showing of exigency required.