E. GRADY JOLLY, Circuit Judge:
A divided panel of this court concluded that the defendants’ motion to suppress evidence in this drug trafficking and firearms case should have been granted by the district court. The panel therefore reversed the convictions of Donnie Lamont Blount and Gaylin Terod Johnson, over the dissent of one panel member. United States v. Blount, 98 F.3d 1489 (5th Cir.1996), reh’g en banc granted, 104 F.3d 58 (5th Cir.1997). We voted to rehear the case en banc, principally to address the application of the Supreme Court’s decision in Illinois v. Gates, 462 U.S. 213, 103 S.Ct. 2317, 76 L.Ed.2d 527 (1983), to statements made by crime scene bystanders who are ordinary citizens with knowledge of specific criminal activity. We conclude that the officers’ initial warrantless entry into the residence was justified by exigent circumstances, that the affidavit for the search warrant was supported by probable cause, and that the district court therefore properly denied the motion to suppress. We affirm Blount and Johnson’s convictions on the drug trafficking charges. We agree with the unanimous panel, however, that the evidence was insufficient to support Blount’s firearms convictions, and we reverse and render a judgment of acquittal on those counts.1
I
On September 13, 1994, Officer Alan Weston of the Houston Police Department’s Violent Gang Task Force received a tip from a confidential informant. The informant stated that he had observed the sale of crack cocaine in a house located at 3717 Campbell Street, in Houston’s Fifth Ward district, an area with a high rate of gang-related drug crimes. The informant did not know the name of the suspect who sold the drugs, but provided Weston with a general description; the informant also told Weston that the suspect had a “large, blue steel pistol” lying on the couch beside him. The informant further stated that the house in question was being-used as a crack house by the Fifth Ward Posse. Officer Weston was well aware that the Fifth Ward Posse was a violent criminal street gang. The informant reported that he had seen several members of that gang at 3717 Campbell.
Weston performed a computer check on 3717 Campbell. He discovered that two months previously, an aggravated sexual assault with a firearm had been reported at that address. The report named “Ricky” and “Lamont” as suspects. On the basis of the detailed information provided by the informant, Weston went before a magistrate judge and obtained a search warrant for the residence at 3717 Campbell. The warrant also authorized the arrest of the unknown [833]*833black male suspect. The defendants do not contest the validity of this warrant.
After obtaining the warrant, HPD officers made a “tentative ID” of the suspect as one Richard J. Thomas, based upon further research that disclosed that (1) Thomas had previously lived down the street from 3717 Campbell, (2) Thomas was known as “Ricky” and matched the physical description given by the informant, and (3) Thomas had a felony record.
At around 6:15 a.m. on September 15, as many as twelve officers from the HPD and the Bureau of Alcohol, Tobacco and Firearms raided the house at 3717. The officers were dressed in official HPD and ATF raid gear, with patches identifying them as law enforcement officials. The officers announced themselves loudly and then immediately rammed the front door of the house to gain entry. A suspect matching Thomas’ description escaped through a rear side door, while officers stationed at the rear attempted to fend off a pit bull dog in the back yard. The suspect escaped over a fence to the north, and the officers lost sight of him.
Inside the house, the officers found crack cocaine, cash and a handgun. It appeared that no one actually lived in the house, and the characteristics of the house suggested to the officers that it was being used as a “smoke house,” where small retail amounts of crack cocaine were sold directly to users.2 The defendants do not contest the validity of this search.
Although some of the agents departed after they were unable to locate the fugitive suspéct, Officer Weston and ATF agents Brown and Gary continued to search. Approximately fifteen to twenty minutes after the raid, the officers noticed Ms. Dorothy Cooksey outside her house. Cooksey appeared agitated. Although Cooksey at first indicated that she saw nothing, when Weston pressed her she explained that several minutes earlier “Ricky” had attempted to force his way into her home in order to hide from police.
Cooksey identified “Ricky” as Richard J. Thomas from the photo carried by Officer Brown; Cooksey said that she knew and feared Thomas, and did not want her name used. She told the officers that Thomas would “end up” at the house on the corner of Bleker and Campbell, which was where Thomas lived, and where he, “Lamont with the Afro” and others “sold dope.” Cooksey stated that the house was a known drug house. The house on the corner to which Cooksey directed the officers was 2302 Bleker Street, and was directly adjacent to the house at 3717 Campbell. Ms. Cooksey lived at 2312/é Bleker, just two houses north of 2302 Bleker.
The remaining officers proceeded to 2302 Bleker. Officer Weston went to the rear of the house while the other officers pounded on the front door, announcing themselves as police and indicating that they needed to speak to the residents. The officers at the front heard one person say “who is it?” and then heard commotion and movement from inside the house. Meanwhile, Officer Weston peered through a four-inch gap in a boarded-over window at the rear of the house; inside Weston observed a black male with an “Afro” style haircut fiddling with the lock on a closet.
The officers continued to knock. After ten or fifteen minutes of knocking and demands by the police, one of the residents called 9-1-1 to report a burglary in progress. Within minutes, marked HPD patrol cars arrived at the scene. After discussing the situation with the new arrivals, Officer Brown and a uniformed patrol officer approached the front door. Defendant Blount, who had an “Afro” haircut, defendant Johnson, and Otis Green, a minor, came out of the house. Blount, Johnson, and Green were all dressed in what Weston described as typical gang-style clothing. The three were immediately patted down, handcuffed and detained on the porch. Blount tried to explain that he had not opened the door because he had been smoking marijuana in a cigar.
[834]*834The officers then made a “protective sweep” to determine whether Thomas or anyone else was hiding in the house. The officers did not obtain permission, but simply entered through the open front door. The officers did not find Thomas, but they observed a razor blade with a white powdery residue in plain view on the kitchen counter. The residue field-tested positive for cocaine.
At this point, the officers exited the house, discussed what to do, and decided to get a search warrant for the house. They thus decided to maintain custody of the house and the detainees while a search warrant was obtained. The detainees were read their Miranda rights after the sweep. Weston prepared an affidavit, describing the escape of the suspect ficom 3717 Campbell, his conversation with Ms. Cooksey, and the events that occurred at 2302 Bleker, including a statement that cocaine residue was found during the sweep of 2302 Bleker.
The affidavit was submitted to the same magistrate judge who, two days earlier, had authorized the search of 3717 Campbell. The magistrate judge issued a search warrant and an arrest warrant for Blount and other persons in control of illegal drugs at the house. During the second, more thorough search of 2302 Bleker, the officers found crack cocaine in wholesale quantities, cash and several firearms, one with a silencer. Some of the drugs and firearms were found in the locked closet at which Weston had observed Blount before the sweep; a .38 caliber revolver bearing Blount’s fingerprints was found on top of a television stand in the living room. After the search was executed, Blount and Johnson were formally arrested.
II
Blount and Johnson were indicted in federal district court for the Southern District of Texas for conspiracy to possess with intent to distribute 50 grams or more of cocaine, in violation of 21 U.S.C. § 846 (Count 1); aiding and abetting such possession, in violation of 21 U.S.C. § 841(a)(1) and 18 U.S.C. § 2 (Count 2); using or carrying a firearm in relation to a drug trafficking offense, in violation of 18 U.S.C. § 924(c)(1) (Count 3); and using or carrying a firearm equipped with a firearm silencer in relation to a drug trafficking offense, in violation of § 924(c)(1) (Count 4).
Blount filed a pre-trial motion to suppress the fruits of an illegal search, which Johnson joined. Blount and Johnson alleged that they were illegally arrested without probable cause, and that the initial, warrantless sweep of 2302 Bleker was also an illegal search. Blount sought suppression of his statement that he had been smoking marijuana, and both defendants sought to suppress the evidence found during the initial sweep and the subsequent execution of the search warrant for 2302 Bleker.
The district court held a pre-trial eviden-tiary hearing on the motion to suppress. The court found that Officer Weston’s peering through the back window was not an unconstitutional search because Weston was legitimately in the back yard to ensure that the suspect they were chasing did not again escape. The court further found that, at the time the defendants were handcuffed and detained, the officers had probable cause to arrest them for harboring a fugitive and for possession of illegal narcotics, and that the initial sweep of the Bleker Street house was a proper protective sweep. Alternatively, the court found that the officers’ actions were justified by exigent circumstances.
Following trial before a jury, Blount and Johnson were both convicted on the drug trafficking counts (Counts 1 and 2). Blount was convicted on the firearms counts, but Johnson was found not guilty (Counts 3 and 4). Both defendants appealed. A divided panel of this court reversed the district court’s denial of the motion to suppress, and vacated the defendants’ convictions on Counts 1 and 2. The panel agreed that insufficient evidence supported Blount’s convictions on Counts 3 and 4. We determined to rehear the appeal en banc. United States v. Blount, 104 F.3d 58 (5th Cir.1997).
Ill
Blount and Johnson contend that the evidence from 2302 Bleker should have been suppressed because the police officers’ initial “protective sweep” into 2302 Bleker was un[835]*835constitutional, and therefore the subsequent search warrant was invalid as it was based upon an affidavit containing evidence obtained during the illegal first search.
The government responds first that the officers’ initial sweep into the Bleker Street house was justified by exigent circumstances, including the “hot pursuit” of a fleeing felon, the danger that contraband or other evidence would be destroyed, and the danger to the officers and bystanders who had begun to gather near the house. Second, the government argues that the initial, brief search of 2302 Bleker was a lawful protective sweep incident to arrest.
In making their various arguments, the defendants strenuously dispute the officers’ reliance on the statements made at the scene by the neighbor, Ms. Cooksey. Blount and Johnson argue that the information received from Cooksey cannot form the basis of a finding of probable cause to believe drugs were being sold from 2302 Bleker Street. They insist that Cooksey’s statements cannot be considered reliable because she is an “unnamed, unknown, untested, and unproven” informant. They argue that the police were required to first set up surveillance on 2302 Bleker to determine whether the information provided by Cooksey could be considered reliable. Blount and Johnson insist that under the Supreme Court’s decision in Gates, tips such as Ms. Cooksey’s must be “corroborated by independent police work” before they can form the basis of probable cause. See Gates, 462 U.S. at 241-246, 103 S.Ct. at 2334-2336.
The government counters that “independent corroboration” of Cooksey’s information was not required under the circumstances of this ease. Principally, the government argues that as an “average citizen,” rather than an anonymous tipster as in Gates, the information that police received from Ms. Cook-sey may legitimately be presumed credible. The government cites a variety of cases in which courts have held that “citizen informants,” “identified bystanders,” victims and crime scene witnesses may generally be presumed credible by police in a way that professional informants are not.
IV
As we have earlier suggested, we elected to rehear this ease en banc in order to explain that the “totality of the circumstances” standard announced in Gates does not impose a requirement of corroboration in all cases. In this context, we iterate our previous authority and hold that, absent specific reasons for police to doubt his or her truthfulness, an ordinary citizen, who provides information to police at a crime scene or during an ongoing investigation, may be presumed credible without subsequent corroboration. We turn now to review the meaning of Gates as it relates to the case before us today.
A
Gates represents a relaxation of the formalities required for support of a search warrant. Before the Supreme Court’s decision in Gates, the federal courts generally applied a somewhat rigid “two-pronged” test to determine whether the statements of an informant could establish probable cause for a search warrant to issue. Under the test derived from Aguilar v. Texas, 378 U.S. 108, 84 S.Ct. 1509, 12 L.Ed.2d 723 (1964), and Spinelli v. United States, 393 U.S. 410, 89 S.Ct. 584, 21 L.Ed.2d 637 (1969), reviewing courts required that the warrant affidavit demonstrate both the informant’s basis of knowledge and offer some indication of the informant’s credibility or the reliability of the information offered. In Gates, the Supreme Court observed that the “two-pronged” approach had become unduly rigid in its application, and reiterated that a simple “totality of the circumstances” test was appropriate for probable cause determinations. 462 U.S. at 230-231, 103 S.Ct. at 2328.
Gates concerned a narcotics investigation prompted by an anonymous tip. Police received an unsolicited, unsigned letter stating that Sue and Lance Gates were involved in selling drugs. The letter specified drug-related transactions that would occur on a particular date. Although police had no prior knowledge of the Gateses, they investigated the tip. The police did not observe either Sue or Lance Gates with drugs or known [836]*836dealers, but they did observe that the unusual facts predicted by the letter — that Sue Gates would drive a car from Illinois to Florida and fly home while Lance Gates would fly to Florida and drive the car home — were accurate. Upon that basis, the police obtained a search warrant for the car and for the couple’s home.
The Supreme Court suggested that, standing alone, the anonymous tip would not be sufficient for a finding of probable cause. However, the Court cited “the value of corroboration of details of an informant’s tip by independent police work.” Id. at 241, 103 S.Ct. at 2334. The Court concluded that because the informant’s tip concerning the Gateses had been corroborated by the officers’ investigation — even though no illegality had been observed — probable cause was established under the totality of the circumstances. Id. at 246, 103 S.Ct. at 2336.
Gates states that probable cause is a “fluid concept” that is “not readily, or even usefully, reduced to a neat set of legal rules,” Id. at 232, 103 S.Ct. at 2329. Blount and Johnson argue, nonetheless, that Gates represents a requirement that the statements of informants be corroborated by subsequent, independent police investigation before they may be considered sufficiently reliable to establish probable cause. Yet Gates itself rejects this argument, noting that “if an unquestionably honest citizen comes forward with a report of criminal activity — which if fabricated would subject him to criminal liability — we have found rigorous scrutiny of the basis of his knowledge unnecessary.” Id. at 233-234, 103 S.Ct. at 2330 (citing Adams v. Williams, 407 U.S. 143, 146-147, 92 S.Ct. 1921, 1923-1924, 82 L.Ed.2d 612 (1972)). Similarly, in United States v. Fooladi, 703 F.2d 180 (5th Cir.1983), a pre-Gafes decision, Judge Rubin of this court noted that “when an average citizen tenders information to the police, the police should be permitted to assume that they are dealing with a credible person in the absence of special circumstances suggesting that such might not be the ease.” Id. at 183 (quoting 1 W. LaFave, Search & Seizure, § 3.4(a), at 592 (1978)). It cannot be said that Fooladi, which was decided under the more stringent requirements of Aguilar and Spinelli, does not remain valid after Gates; in fact, the common-sense approach adopted by the Supreme Court in Gates simply strengthens the position adopted in Fooladi.
There is no set requirement that all tips be corroborated by subsequent police investigation in order to be considered credible. Whether subsequent corroboration is necessary must be determined in the light of the totality of the circumstances presented by the particular set of facts. We conclude that under the totality of the circumstances in this case, Ms. Cooksey’s statements provided the police with probable cause to believe that illegal narcotics would be found in 2302 Bleker.
When the police first noticed Ms. Cooksey, they had already amassed a substantial amount of information from their early-morning raid at 3717 Campbell. The officers knew that a black male, tentatively identified as Ricky Thomas, had been selling crack cocaine from 3717 Campbell. Officer Weston testified at the suppression healing that 3717 Campbell matched the description of a “smoke house,” used only to sell small retail amounts of crack cocaine directly to users, some of whom may be permitted to remain at the house to smoke the cocaine. These officers had extensive experience with drag operations. Based on that experience, the officers knew that it was probable that there would be a more heavily-guarded “stash house” nearby, where the bulk of drugs and cash were kept, and from which the dealers might sell crack cocaine in wholesale amounts to street dealers. The officers expected other individuals, probably gang members with Thomas, to be involved in the operation. The officers also believed that Thomas and someone named “Lamont” had committed an aggravated sexual assault with a firearm at 3717 Campbell two months before the raid.
The information that Ms. Cooksey provided to the officers “fit” with what they already knew. From the picture earned by one of the officers, Cooksey confirmed that their suspect, whom she knew as “Ricky,” was Richard J. Thomas. Cooksey indicated that Ricky did not live at 3717 Campbell, but at 2302 Bleker. She confirmed that Thomas [837]*837was involved in selling drugs, and also connected Thomas with a “Lamont” through her statement that “Lamont with the Afro” and others sold drugs from 2302 Bleker. Furthermore, Cooksey' identified 2302 Bleker as a known drug house in her neighborhood.
The officers had no reason to disbelieve Ms. Cooksey, or to question her motives or credibility. Cooksey was not an anonymous tipster or a paid informant. Although the warrant affidavit does not give Cooksey’s name, the affidavit states that the information was solicited from a female who (1) lived at 2312^ Bleker, two houses away from the subject house, (2) knew and feared the fugitive Ricky Thomas, and (3) had observed Thomas attempt to kick in her door in an effort to hide from police. This information adequately identifies Ms. Cooksey as a citizen providing information during a crime scene investigation in her immediate vicinity.
Unlike the anonymous tipster in Gates, whose unsolicited information concerned people unknown to police, Cooksey’s statements were solicited by police after they observed her outside her house on the morning in question. Cooksey’s statements fit into the end of an ongoing investigation, rather than prompting the beginning of a new one. The immediacy of the investigation, with a fleeing felon on the loose, is also a relevant consideration. Under the circumstances, “independent police corroboration” of the information given by Ms. Cooksey was not required. We conclude that under Gates, and under our specific precedent of Fooladi, Cooksey’s statements provided the police with probable cause to believe that (1) Ricky Thomas might be hiding in 2302 Bleker, and (2) illegal drugs would be found at 2302 Bleker.
B
The government argues that Cooksey’s statements, combined with the information that the officers had already obtained, established exigent circumstances justifying the officers’ initial entry into 2302 Bleker. Although a warrantless entry into a home is presumptively unreasonable, entry may be justified by exigent circumstances. United States v. Rico, 51 F.3d 495, 501 (5th Cir.), cert. denied, — U.S. —, 116 S.Ct. 220, 133 L.Ed.2d 150 (1995) (citing United States v. Richard, 994 F.2d 244, 247 (5th Cir.1993)). The government bears the burden of proving that an exigency existed. Id. (citing United States v. Thompson, 700 F.2d 944, 946 (5th Cir.1983)). In this case, the district court specifically found that exigent circumstances existed. This determination is reviewed only for clear error. United States v. Howard, 106 F.3d 70, 74 (5th Cir.1997) (citing Richard, 994 F.2d at 248). We conclude that the district court did not clearly err.3
Because it is essentially a factual determination, there is no set formula for determining when exigent circumstances may justify a warrantless entry. Exigent circumstances generally exist where there is a risk that the officers or innocent bystanders will be endangered, or that evidence will be destroyed. In Rico, we identified a non-exhaustive list of factors that may be considered in determining whether exigent circumstances existed:
(1) the degree of urgency involved and the amount of time necessary to obtain a warrant;
(2) the reasonable belief that contraband is about to be removed;
(3) the possibility of danger to the police officers guarding the site of contraband while a search warrant is sought;
(4) information indicating that the possessors of the contraband are aware that the police are on their trail; and
(5) the ready destructibility of the contraband and the knowledge that efforts to dispose of narcotics and to escape are characteristic behavior of persons engaged in the narcotics traffic.
Id. at 501 (citing Richard, 994 F.2d at 248) (internal brackets and quotation marks omitted).
[838]*838The exigent circumstances analysis focuses upon the reasonableness of the officers’ investigative tactics leading up to the warrant-less entry. Our purpose is not to examine each act in isolation and inquire whether the officers could have acted differently. If “reasonable minds may differ” the courts should not second-guess the judgment of experienced law enforcement officers concerning the risks of á particular situation. Howard, 106 F.3d at 76.
In this case, the officers faced two separate, but related concerns when they first approached 2302 Bleker: the officers were attempting to apprehend and arrest Ricky Thomas, and the officers reasonably believed that a violent drug-trafficking gang, to which Thomas belonged, was operating from 2302 Bleker as its stash house.
Blount and Johnson argue that the officers were required to set up surveillance of the house and obtain a warrant; they contend that any exigency that existed was “manufactured” by the officers when they approached the front door of 2302 Bleker. It is true that the prosecution may not rely upon an exigency that the police themselves created through unreasonable investigatory tactics. Richard, 994 F.2d at 248. This, however, is not such a case.
As we have already concluded, Ms. Cooksey’s statements, combined with the information the officers had already obtained, gave the officers probable cause to believe both that Thomas could be hiding in 2302 Bleker and that the other residents of 2302 Bleker were engaged in drug trafficking. This fast-moving and unpredictable scene in a tough neighborhood infected by a violent drug-trafficking gang was simply not a case where the officers could safely set up surveillance while they awaited a search warrant.
First, the officers were continuing an immediate search for a fleeing felon who had already escaped once from a large group of officers. The officers had confirmed that Thomas was engaged in the sale of crack cocaine, and he was a suspect in an armed sexual assault. The officers reasonably believed that Thomas was aimed, dangerous, and would attempt to evade capture. It would have been virtually impossible for the officers to 'covertly secure 2302 Bleker against Thomas’ escape.
Moreover, Thomas was not the officers’ sole concern. The officers reasonably believed that 3717 Campbell and 2302 Bleker were two houses being employed by a violent criminal street gang in its cocaine trafficking operation. The house at 2302 Bleker, the officers believed, was the “stash” house from which the conspiracy operated. Considering that 2302 Bleker was a mere fifteen feet away from 3717 Campbell, where as many as twelve law enforcement officers had executed an early morning raid, it would be unreasonable to suppose that the residents of 2302 Bleker were not aware of the officers’ presence.4
Under the circumstances, the officers’ decision to immediately approach 2302 Bleker and ask to speak to the residents was reasonable. They were looking for Ricky who might well have been in the house. They had been told by a neighbor that it was his residence, and that at some point he would land there. They had been told by that neighbor that drugs were sold there. They knew that Ricky sold drugs. They had reason to believe that members of a violent gang were also involved. They had reason to believe that 2302 Bleker was the “stash house” for the drug operation they had earlier uncovered. The fact that the residents refused to come to the door or to communicate with the officers but were heard moving around within the house added to an intense and volatile situation and — importantly—to the likelihood that significant evidence was being destroyed. We have previously observed that the destruction of narcotics .is a “characteristic behavior” of those engaged in drug trafficking. Thompson, 700 F.2d at 948.
The situation also remained potentially explosive from the officers’ reasonable point of view. • Not only are firearms “tools of the trade” in illegal drug trafficking, Howard, [839]*839106 F.3d at 75, but the fugitive member of the drug conspiracy had previously been observed with a handgun, and a firearm had been found in the raid on the first house.5
These concerns were not eliminated at the point when the three residents of 2302 Bleker exited the house. As far as the officers knew at the time, Thomas and perhaps others involved in the drug trafficking operation might still be hiding in the house, barricading themselves against an arrest. Furthermore, any individuals who remained inside might still be destroying evidence. If so, a sweep through the house was the officers’ only opportunity to recover remnants of attempts at drug destruction, which would likely be lost during the intervening time required to obtain and execute a search warrant. Importantly, several onlookers had begun to gather near the house, who would be endangered if a barricade and shoot-out were allowed to develop. Against the backdrop of these facts, the officers had to decide whether to make an entry and fully secure the crime scene or to “pull out,” leaving outside security surrounding the house and delay further action until a warrant application could be prepared and a warrant obtained. The decision that the officers made was not unreasonable. To hold otherwise would ignore the interplay between the officers’ continuing efforts to apprehend Thomas and the officers’ reasonable belief that 2302 Bleker was a “stash” house — connected with 3717 Campbell that the officers had earlier raided— where drugs were being kept and sold by dangerous gang members in a violence-prone section of the city.
Finally, we underscore a point that cannot be brushed aside: our standard of review is highly deferential. Under the circumstances, we conclude that the district court was not clearly erroneous in its finding that exigent circumstances justified the officers’ initial entry into 2302 Bleker.6
V
Thus, we sum up: Based upon Cooksey’s statements and the information that the officers had already amassed, the officers had probable cause to believe that Thomas might be hiding in 2302 Bleker, and that drugs or other contraband would be found there. We further have concluded that the officers’ investigative tactics were not unreasonable, and that the district court’s finding that exigent circumstances existed was not clearly erroneous. Consequently, the evidence referred to in the affidavit was properly obtained and supported a finding of probable cause. The search warrant was therefore valid, and the district court correctly denied Blount and Johnson’s motion to suppress the evidence found at 2302 Bleker.
[840]*840Blount and Johnson’s convictions on Counts 1 and 2 are therefore AFFIRMED. Blount’s convictions on Counts 3 and 4 for drug-related firearms violations are REVERSED, and a judgment of acquittal is RENDERED on those counts.
AFFIRMED in part; REVERSED in part; and RENDERED in part.