*177OPINION OF THE COURT1
FLAHERTY, Chief Justice.These consolidated cases are appeals from orders of the Superior Court affirming the judgments of sentence of Joseph Carlton and Donald Carlton after they were convicted of drug trafficking offenses. This court granted the appellants’ petitions for allowance of appeal to determine whether the police violated the “knock and announce” rule when they executed a valid search warrant and seized crack cocaine, a handgun, ammunition, and drug paraphernalia.
I. FACTS AND PROCEDURAL HISTORY
On January 28, 1992, Philadelphia police purchased crack cocaine from a house at 3229 Fontain Street in Philadelphia from Joseph Carlton. Based on this purchase, police secured a search warrant for 3229 Fontain Street on January 30, 1992. Later that day, police conducted another cocaine purchase, this time from Donald Carlton, using a marked ten dollar bill. Shortly after the purchase, police saw Donald Carlton leave the house. They radioed a team of backup officers, who were waiting to execute the search warrant. The backup officers arrested Donald Carlton and immediately thereafter executed the search warrant.
In executing the warrant, the officers knocked on the front door and shouted, “Police.” After waiting twenty to thirty seconds and receiving no response, the police, using a battering ram, battered the door down. The officers did not announce their purpose before entering the house. Upon entering the house, police arrested Joseph Carlton, who was sitting in the dining room with two vials of crack cocaine in his possession. In various parts of the house, police also found a .38 caliber revolver and ammunition, a bag containing 147 additional vials of crack cocaine, a Wells Fargo identification card for Joseph Carlton showing an address of 3229 Fontain Street and a Pennsylvania Department of Welfare card in the *178name of Donald Carlton. The trial court stated: “Identification showing that the defendants used 8229 Fontain Street as their address was found in the house.” Slip Op., trial court, at 11.
Prior to trial, both appellants moved for suppression of all physical evidence seized in the house, alleging that the police lacked probable cause to search the house and that the police violated the appellants’ rights when they executed the search warrant. The appellants did not move for suppression of the drugs they sold to police. Appellants were tried together in a non-jury trial. After denying the motions to suppress, the trial court convicted the appellants of the following offenses:
Joseph Carlton:
One count of possession with intent to deliver a controlled substance, Section 13(a)(30) of the Drug Device and Cosmetic Act (Drug Act), Act of April 14, 1972, P.L. 233, No. 64, § 13(30), 35 P.S. § 780-113(a)(30),
One count of possession of drug paraphernalia, Section 13(a)(33) of the Drug Act, 35 P.S. § 780—113 (a)(33) and One count of criminal conspiracy, 18 Pa.C.S. § 903.
Donald Carlton:
Two counts of possession with intent to deliver a controlled substance, Section 13(a)(30) of the Drug Act, 35 P.S. § 780-113(a)(30),
One count of possession of drug paraphernalia, Section 13(a)(33) of the Drug Act, 35 P.S. § 780-113(a)(33), and Criminal conspiracy, 18 Pa.C.S. § 903.
Joseph Carlton was sentenced to one to two years imprisonment for possession with intent to deliver a controlled substance, followed by concurrent two-year terms of probation for criminal conspiracy and possession of drug paraphernalia. Donald Carlton received a sentence of twenty-one to forty-two months imprisonment for the first count of possession with intent to deliver a controlled substance, a concurrent term of twenty-one to forty-two months imprisonment for a second count of possession with intent to deliver a controlled substance, followed by two concurrent terms of two years proba*179tion for criminal conspiracy and possession of drug paraphernalia.
On appeal, the Carltons argued that the police violated their rights because the search warrant affidavit did not state probable cause and because the police violated the knock and announce rule.2 The Superior Court panel, with one judge dissenting, affirmed the judgments of sentence, holding that exigent circumstances justified the officers’ immediate entry into the house without announcing their purpose. This court granted both appellants’ petitions for allowance of appeal to determine whether the police violated the knock and announce rule.
II. DONALD CARLTON
Donald Carlton complains that the police violated his constitutional rights when they entered 8229 Fontain Street without announcing that their purpose was to execute a search warrant. He was arrested on the street near the house and was not inside the house when police entered.
In Pennsylvania, defendants charged with possessory offenses have automatic standing to litigate a suppression motion. Commonwealth v. Sell, 504 Pa. 46, 470 A.2d 457 (1983). In Commonwealth v. Gordon, 546 Pa. 65, 683 A.2d 253 (1996) and Commonwealth v. Peterson, 535 Pa. 492, 636 A.2d 615 (1993) police conducted warrantless entries into abandoned buildings which were occupied by the defendants, where they seized contraband. We held that although defendants charged with possessory offenses have standing to file a motion to suppress the materials seized by police, they must, as part of their case for suppression, meet the threshold requirement of demonstration of a privacy interest which was “actual, societally sanctioned as reasonable, and justifiable in the place invaded.... ” Peterson, 535 Pa. at 497, 636 A.2d at 617. In Gordon we explained that in order to establish a *180legally cognizable expectation of privacy, a defendant must establish “either a possessory interest, a legitimate presence or a characteristic of ownership ... from which society could recognize an expectation of privacy.” Gordon, 546 Pa. at 73, 683 A.2d at 257. In short, in order for a defendant accused of a possessory crime to prevail in a challenge to the search and seizure which provided the evidence used against him, he must, as a threshold matter, establish that he has a legally cognizable expectation of privacy in the premises which were searched.
Donald Carlton, therefore, must establish that he had an expectation of privacy in the premises entered by police. The trial court stated: “Identification showing that the defendants used 3229 Fontain Street as their address was found in the house.” Slip Op. at 11. This statement, which is tantamount to a finding of fact, establishes that Donald Carlton had the requisite privacy interest in the premises.3 Having established that, he may challenge the propriety of the search and seizure.
III. JOSEPH CARLTON
In Joseph Carlton’s case, the sole issue is whether the trial court should have ordered suppression of evidence based on an alleged violation of the knock and announce rule when the police executed a search warrant for the house. Because *181the Commonwealth’s evidence established that Joseph Carlton was present when police entered the house and that he received mail at that address, there is sufficient evidence of record to establish that he had a reasonable and legitimate expectation of privacy in the house at 3229 Fontain Street. Both Joseph and Donald Carlton, therefore, have raised a legally cognizable challenge to the manner in which the search warrant was executed.
IV. CHALLENGE TO THE SEARCH AND SEIZURE
Rule 2007 of the Pennsylvania Rules of Criminal Procedure, Pa. R.Crim.P.2007, sets forth the manner in which the police may enter premises to execute a search warrant:
Rule 2007. MANNER OF ENTRY INTO PREMISES
(a) A law enforcement officer executing a search warrant shall, before entry, give, or make reasonable effort to give notice of his identity, authority and purpose to any occupant of the premises specified in the warrant, unless exigent circumstances require his immediate forcible entry.
(b) Such officer shall await a response for a reasonable period of time after his announcement of identity, authority, and purpose, unless exigent circumstances require his immediate forcible entry.
(c) If the officer is not admitted after such reasonable period, he may forcibly enter the premises and may use as much physical force to effect entry therein as is necessary to execute the search.
Thus, unless there are exigent circumstances, Rule 2007 requires that police officers executing a search warrant should make a reasonable effort to knock and announce their identity and purpose and then wait a reasonable amount of time for the occupants to respond before entering private premises.
The primary purpose of the knock and announce rule is to prevent resistance to lawful authority based on the occupant’s efforts to protect his privacy expectation against unauthorized entry of persons unknown to him. Commonwealth v. McDonnell, 512 Pa. 172, 516 A.2d 329 (1986). In addition, the knock *182and announce rule prevents violence and physical injury to the police and the occupants and protects an occupant’s privacy expectation against unauthorized entry of unknown persons, and prevents property damage resulting from forced entry during the execution of a search warrant. Commonwealth v. Crompton, 545 Pa. 586, 682 A.2d 286 (1996).
In the present case, the police announced their identity, but did not announce their purpose when executing the search warrant. We have recognized four exceptions to the requirements of the knock and announce rule:
1. the occupants remain silent after repeated knocking and announcing;
2. the police are virtually certain that the occupants of the premises already know their purpose;
3. the police have reason to believe that an announcement prior to entry would imperil their safety; and
4. the police have reason to believe that evidence is about to be destroyed.
Commonwealth v. Means, 531 Pa. 504, 508, 614 A.2d 220 (1992). If the Commonwealth establishes any of these exigencies, the police may force entry without knocking, announcing their identity and purpose, or waiting for the occupant to respond. Means.
At the motion to suppress, the Commonwealth argues the presence of exigent circumstances as follows:
My other argument, I indicated there were two, your honor, would be at the point that you don’t have any response from inside and you know that one of your two suspects that has sold drugs prior, two days prior including that day, is already walking down the street, at that time, your honor. I would argue that exigent circumstances do exist to break in the door at that point.
Because at that point, your honor, they know they’ve got one and all he’s got is money on him, they know that drugs have been sold from inside that location on that day very day, hours before—actually, I don’t think it’s hours before, minutes before, excuse me, I stand corrected, minutes be*183fore, just five minutes before, and at that point, your honor, where there’s no response the logical thing to think is, great we’re going to stand out here and the person inside is flushing the drugs down the toilet, or in some way destroying them. So I would argue that at that point they do have exigent circumstances to go in and I would ask you to deny the motion.
N.T. 9/30/92, 62-63.
The Commonwealth’s position, in sum, is that because drugs were sold from within the house five minutes before the execution of the warrant, and because one of the two suspects was in custody outside of the house and he did not have drugs on his person, and there was no response to police announcing their identity, whoever remained in the house was destroying evidence.
The Commonwealth’s claim of exigent circumstances is flawed. That drugs were sold minutes before suggests nothing except that drugs are probably still on the premises. Donald’s arrest without drugs also suggests only that drugs remain on the premises. And that police received no response to their announcement of their identity is not surprising, for there is no requirement that anyone open the door to their dwelling in the absence of police statement of their authority and purpose. In a free society, the mere presence of police does not require an individual to throw open the doors to his house and cower submissively before the uniformed authority of the state. As this court stated in Commonwealth v. McDonnell, 512 Pa. 172, 176-77, 516 A.2d 329, 330-31 (1986):
The “knock and announce” rule’s origins pre-date the United States Constitution. It was born in English Common Law and was subsequently adopted in America. In recent times, the “knock and announce” rule has assumed a Constitutional dimension. Both our Court and United States Supreme Court have held that the Fourth Amendment’s prohibition against unreasonable searches and seizures applies to the manner of a warrant’s execution. Ker v. California, 374 U.S. 23, 83 S.Ct. 1623, 10 L.Ed.2d 726 (1963); Commonwealth v. Newman, 429 Pa. 441, 240 A.2d *184795 (1968). Even a valid warrant may not be executed in an unreasonable manner; unreasonableness is determined on a case-by-case basis. Id. The rule’s primary purpose is to prevent resistance to lawful authority based on the occupant’s efforts to protect his privacy expectation against unauthorized entry of persons unknown to him.
In Commonwealth v. Newman, we specifically stated: “[W]e hold that the forcible entry without announcement of purpose violates the Fourth Amendment.” 429 Pa. 441, 449, 240 A.2d 795, 799 (1968).
Newman's categorical statement of its holding notwithstanding, the knock and announce requirement is a rule of reason. There is a presumption that the police will be required to knock and announce their identity, their purpose and their authority, but this requirement will be relaxed in the presence of exigent circumstances. Accordingly, we now hold that in the absence of exigent circumstances, forcible entry without announcement of purpose violates Article 1, Section 8 of the Constitution of Pennsylvania, which prohibits unreasonable searches and seizures.4
In this case, there were no exigent circumstances. Police, therefore, were required to knock and announce their identity, purpose, and authority. If police had identified themselves and stated their authority and purpose, the absence of a response within a reasonable time would have justified a forced entry. In the absence of a statement of *185authority and purpose, however, it was reasonable and within their constitutional rights that the occupants did not respond. Police may not now bootstrap themselves into exigent circumstances by claiming that the reasonable failure to respond, which they themselves may have caused, was justification for forced entry.
The Superior Court adopted the trial court’s conclusion that there were exigent circumstances by citing the trial court’s opinion as follows:
[T]he police had just made an arrest for the sale of drugs immediately outside the house. The person arrested, Donald Carlton, was the brother of the person who had sold drugs to the police on the 28th of January. Although they did not know this particular fact at the time, the police had personal knowledge that at least two persons were engaged in selling drugs from the house. The police could reasonably believe that the other person who had sold drugs from the house, Joseph Carlton, would conclude that his brother had been arrested when he did not return from the drug sale and would destroy the drugs that were in the house. Such a situation falls within the “exigent circumstances” exception to the strict enforcement of the “knock and announce” rule.
Slip Op. at 5-6.
The lower courts’ attempt to justify the battering down of the door are also unavailing. The courts’ rationale was, in essence that the suspect remaining in the house would destroy evidence when his co-conspirator did not return “from the drug sale.” There are at least two infirmities in this rationale. The first is that there is no evidence that Donald was about to engage in a drug transaction when he was arrested. In fact, the evidence was that when he was arrested, he had no drugs on his person.5 The second infirmity is *186that even if Donald had been on his way to a drug sale, the lapse of time between his arrest and the execution of the warrant was so short that Joseph would have had no reason to be alarmed by Donald’s absence.6
In sum, there were no exigent circumstances and it was error to fail to suppress the evidence seized as a result of the search of the house. Because we have determined that both Donald and Joseph Carlton had a legitimate expectation of privacy in the residence at 3229 Fontain Street, the evidence seized should have been suppressed as to both defendants.
However, the evidence of the drug sales to police from the residence at 3229 Fontain Street remains in the case and the convictions of possession with intent to deliver a controlled substance and criminal conspiracy shall remain undisturbed. The convictions and the judgments of sentence as to possession of drug paraphernalia are vacated as to both Donald and Joseph Carlton.
The Superior Court’s order affirming the judgments of sentence is vacated and the convictions and judgments of sentence are modified as indicated above.
ORDER
PER CURIAMAnd now this 10th day of November, 1997, this court’s order dated August 22, 1997 is modified as follows: The conviction *187and judgment of sentence with respect to possession with intent to deliver the 149 vials of cocaine found inside the premises is vacated and remanded for a new trial, as is the conviction and judgment of sentence with respect to possession of drug paraphernalia. The convictions of the possession and sale of three vials of cocaine to an undercover police officer and of conspiracy are affirmed, but the sentences for these crimes are vacated and the case is remanded for resentencing for these convictions.
NEWMAN, J., files a dissenting opinion which is joined by CASTILLE, J.. This case was reassigned to this writer on May 14, 1997.
. The knock and announce rule is a requirement that police must announce their presence, authority and purpose before a person’s privacy may be disturbed.
. We have examined the record, including the notes of testimony of the suppression hearing and post trial motions, and are unable to find any discussion of Donald’s residence, except that defense counsel argued at suppression that there was no evidence that Donald lived at 3229 Fontain Street. The purpose of this argument was to claim that Donald could not have constructively possessed the drug paraphernalia found in the house because it was not established that he was a resident. Apart from this argument, there is no mention of Donald’s residence and there is no apparent awareness on the part of the court or counsel that Donald's residence may have been relevant to meet the threshold requirement that he had a legally cognizable privacy interest in the residence at 3229 Fontain Street as a part of his claim that the execution of the search warrant was defective. Where the trial court was not made aware of the issue that is now raised, but made a finding which resolves the issue based on the evidence it had before it, we will not second-guess the finding of the trial court based on arguments which it did not consider.
. The requirement that police announce their identity, purpose and authority is of ancient origin. Although Semayne’s Case, 50 Co Rep. 91a, 91b, 77 Eng. Rep. 194, 195 (K.B.1603), which required that an officer "ought to signify the cause of his coming," is often cited as the judicial source of the common-law knock and announce rule, Semayne’s case itself refers to a statute enacted in 1275 and indicates that this statute was "but an affirmance of the common law.” Wilson v. Arkansas, 514 U.S. 927, 932 n. 2, 115 S.Ct. 1914, 1917 n. 2, 131 L.Ed.2d 976, 981 n. 2 (1995).
The English common law rule that a door may be broken down once admittance was refused was incorporated into Pennsylvania law by way of a statute, Act of Dec. 23, 1780, ch. 925 § 5, in 10 Statutes at Large of Pennsylvania 255 (J. Mitchell & H. Flanders comp.1904). Id. at 933, 115 S.Ct. at 1917, 131 L.Ed.2d at 982.
. Officer Joyce Reilly, who participated in the execution of the search warrant at 3229 Fontain Street, testified that she stopped Donald Carlton before executing the search warrant, patted him down, and placed him in the police van. She continued:
Q. Whose person was the buy money on, officer?
*186A. Donald.
Q. And what, if anything else, was confiscated from Donald?
A. Just the $800 and the buy money.
N.T. 4/9/92, 30-31.
. The Commonwealth also argues in the Joseph Carlton case that exigent circumstances existed because Joseph may have witnessed Donald's arrest. We have plainly and repeatedly stated that police may not create their own exigencies by making arrests within the sight of co-conspirators. Commonwealth v. Mason, 535 Pa. 560, 637 A.2d 251 (1993); Commonwealth v. Melendez, 544 Pa. 323, 676 A.2d 226 (1996). As we stated in Melendez: "Mere speculation that evidence may be destroyed because suspects may learn of police activity is inadequate to justify a warrantless entiy, and in any event, police may not bootstrap themselves into exigencies by their own conduct.” 544 Pa. at 333, 676 A.2d at 231.