In considering appellants’ contention that evidence of methamphetamine manufacture should have been suppressed, we must determine, inter alia, whether violation of a state trespass law by its law enforcement officers compels, under principles of federalism, suppression of evidence obtained as a result and offered to prove violation of federal law. Appellants also contend that the district court erred in sentencing, by its assessment of drug quantity and enhancement for possession of a firearm and leadership roles. Finding no error, we AFFIRM.
I.
In April 1990, state narcotics officers in Arkansas received information that appellant Cullen Reed Harris was involved in drugs and may have been concealing them on his property in Glenwood, Arkansas. And that July, a confidential informant (Cl) reported that appellant Tom Wilkinson Eastland was using a portable lab to manufacture and distribute methamphetamine in Texas, Arkansas, and Oklahoma. The Cl further advised that Ronnie Dale Gearhart was involved in the manufacture and distribution of methamphetamine, and reported that he (the Cl) had been dealing with Gearhart and Eastland for approximately five years. The Cl believed that the base of the operation was run by a one-armed man, subsequently identified as Harris; and the Cl informed that Harris would contact Eastland at least twice a month for *763 the profits from the sale of methamphetamine. That same month, the police received additional information linking East-land and Harris, and identifying Gearhart as one of Eastland’s main distributors.
State investigators in Arkansas and Texas compiled numerous reports detailing the activities of Eastland, Harris, and Gearhart from September 1990 to March 1991; they believed that Harris and Eastland were conducting a multi-state operation to manufacture, distribute, and possess methamphetamine. Harris was described as the “financier” of the Eastland methamphetamine manufacturing organization.
In an unrelated incident, Deputies Tom Hall and Jeff Duck received information from a Cl on March 16, 1991, of suspicious activity in a wooded area of Leon County, Texas. Among other things, there had been several burglaries in the area during the past few months. The deputies approached the property and observed tire tracks on a trail, which was covered , by plum bushes (two to three feet in height), leading to the heavily wooded-area. The property was surrounded by a barbed wire fence; the entrance gate was chained and locked; and “no trespassing” signs were posted. Suspecting that the wooded property contained hidden stolen goods, the deputies climbed over the gate and entered the property to investigate. They discovered two wood frame buildings, and detected a faint odor associated with a methamphetamine laboratory.
On March 20, Sheriff Wilson notified Department of Public Safety (DPS) narcotics Lieutenant Stewart of the deputies’ findings. Stewart dispatched Sergeants Brake-field and Von Allen to investigate; they entered the property and observed a motor home, but did not detect an odor of a chemical laboratory or otherwise see suspicious activity.
On March 21, Sheriff Wilson learned that the property was owned by Harris, who had an associate named Eastland; that both had criminal records involving, contraband substance violations 1 , and that both were the object of a lengthy investigation in the Houston area. Sergeant Hammonds, with the Houston DPS office, _ who had been actively investigating the activities of Eastland and Harris since September 1990, supplied additional intelligence information on Eastland and Harris’s involvement with methamphetamine production and distribution.
That day, Sergeants Brakefield and Rhynsburger returned to the property in search of evidence of a clandestine laboratory. As they approached a wood frame building, they detected a strong odor associated with a methamphetamine laboratory. Accordingly, they obtained a search warrant that night, and arrested Harris, East-land, and Gearhart as they exited the motor home. A subsequent search of the property uncovered an operating methamphetamine laboratory. The officers recovered 47.68 pounds of methamphetamine, and 111.62 pounds of phénylacetone.
The next day, March 22, the officers executed a search warrant at Eastland’s residence in Spring, Texas, and discovered twelve firearms 2 ; however, they were .missing when federal ATF agents returned with a warrant to seize them. On March 22, the state officers also executed a search warrant at Harris’s residence in Glenwood, Arkansas. Among items seized were four firéarms, 3 a triple beam scale, cash total- *764 ling approximately $212,000, marijuana, a jar containing methamphetamine/ephedrine residue, and a film canister containing methamphetamine residue.
Eastland and Harris were charged with conspiracy to manufacture more than 1000 grams of methamphetamine in violation of 21 U.S.C. §§ 846 and 841(a)(1) (count one), and the manufacture of 1000 grams or more of a mixture or substance containing a detectable amount of methamphetamine, in violation of 21 U.S.C. § 841(a)(1) (count two). The indictment stated that the conspiracy began on or about March 18, 1991, and continued until on or about March 21, 1991.
Prior to trial, Gearhart provided DPS with information on Eastland and Harris. He reported that Eastland had asked him to help manufacture methamphetamine; had offered to pay him after the manufacture and sale of same; and was present at the laboratory, and gave instructions regarding the manufacturing process. He also stated that Harris assisted in setting up the laboratory and in processing the methamphetamine.
Gearhart subsequently testified at trial that he became involved with Eastland’s methamphetamine business in 1988, first as a purchaser of precursor chemicals and then as a methamphetamine distributor; that he received one quarter pound on approximately two occasions, and then a half a pound for approximately one and a half months; that he paid approximately $750 per ounce; and that he received methamphetamine from Eastland at his house in Spring, Texas on two occasions.
A jury found Harris and Eastland guilty as charged. At sentencing, over objection, the district court applied a three-level increase, pursuant to Sentencing Guideline § 3B 1.1(b) for their respective roles in the offense, and a two-level increase for possession of a firearm during commission of the offense, pursuant to U.S.S.G. § 2D1.1(b)(1). Eastland and Harris were sentenced, inter alia, to life imprisonment as to each count, to be served concurrently.
II.
Appellants contest the denial of their suppression motion; and, for their sentences, contest the rulings on drug quantity, leadership roles, and weapons possession.
A.
On two grounds, Eastland and Harris challenge the district court’s refusal to suppress evidence of methamphetamine manufacturing, obtained through execution of the search warrant on March 21. First, they contend that information used in the affidavit to obtain the warrant, such as the faint chemical odor detected on March 16,' stemmed from an unreasonable search of Harris’s property on March 16, violative of the Fourth Amendment. According to appellants, law enforcement officers may not enter “open fields” on private property without some degree of justification. 4 Second, they maintain that, because, prior to execution of the warrant, Texas law enforcement officers trespassed onto Harris’s property in violation of state law, the court should have suppressed the evidence. We reject both contentions.
1.
Appellants assert that some level of justification — whether it be probable cause or, at least, reasonable suspicion — is a prerequisite for warrantless police intrusions onto open fields. They contend that otherwise, the open fields exception will swallow the rule — the Fourth Amendment — and destroy a person’s limited expectation of privacy engendered by, inter alia, state laws prohibiting non-consensual entry.
In
Hester v. United States,
It is well-established that the Fourth Amendment does not apply to observations while standing on open fields.
See United States v. Pace,
Justification for a search or seizure under the Fourth Amendment is required because it demands reasonableness.
5
See Terry v. Ohio,
2.
Appellants contend that the admission of evidence derived from an unlawful trespass by state officers 8 contravened principles of federalism. 9 According to appellants, because the Texas state exclusionary statute, see Vernon’s Ann.Texas C.C.P. art. 38.23, would operate to exclude evidence seized pursuant to the March 21 warrant, 10 the evidence should be similarly inadmissible in federal court. We find no basis for so holding, either under the Constitution or pursuant to our supervisory powers.
The exclusionary rule is not “a personal constitutional right”, but is “a judicially created remedy designed to safeguard Fourth Amendment rights generally through its deterrent effect”.
United States v. Calandra,
[T]he proper inquiry in determining whether to exclude the evidence ... is not whether the state officials’ actions in arresting him were “lawful” or “valid under state law.” The question that a federal court must ask when evidence secured by state officials is to be used as evidence against a defendant accused of a federal offense is whether the actions of the state officials in securing the evidence violated the Fourth Amendment to the United States Constitution.
Walker,
In determining the reach of the Fourth Amendment, it is well-established that federal law controls.
See California v. Greenwood,
Individual States may surely construe their own constitutions as imposing more stringent constraints on police conduct than does the Federal Constitution. We have never intimated, however, that whether or not a search is reasonable within the meaning of the Fourth Amendment depends on the law of the particular State in which the search occurs.
Id.
at 43,
Citing
United States v. Robinson,
Where there is "some strong social policy”, federal courts may extend exclusionary rules of evidence beyond constitutional and statutory requirements.
On Lee v. United States,
[WJhen a federal court sitting in an exclusionary state admits evidence lawlessly seized by state agents, it not only frustrates state policy, but frustrates that policy in a particularly inappropriate and ironic way. For by admitting the unlawfully seized evidence the federal court serves to defeat the state’s effort to assure obedience to the Federal Constitution.
Id.
at 221,
Appellants maintain that we should apply the rationale of the Elkins Court and, in the name of federalism, similarly exclude evidence obtained in violation of state law. According to appellants, “[ajllowing federal prosecutors to use evidence obtained in violation of state law thwarts the authority and ability of the states to protect their own citizens”. For a number of compelling reasons, we refuse to so exercise our supervisory power.
First, and most significantly, appellants’ contention is foreclosed by
Walker,
In addition, a number of obvious, strong policy considerations' militate against the
*767
exclusion of evidence obtained in violation of state law. For example, such a rule would disrupt uniformity of evidentiary rules among federal courts, and involve them in difficult interpretations of state statutory and constitutional law. Accordingly, we likewise hold that the contours of the exclusionary rule to be applied in federal court are generally determined by federal, not state, law, even where evidence is obtained solely by state officers.
See United States v. Sutherland,
B.
Appellants challenge the drug quantity amounts used to calculate base offense levels for sentencing. We review only for clear error a district court’s findings concerning the quantity of drugs involved,
United States v. Ponce,
The district court found appellants responsible for 47.68 pounds of methamphetamine and 111.62 pounds of phenylacetone, derived from the following seized objects: (1) four flasks containing 47.68 pounds of methamphetamine in liquid form; (2) a sep-aratory funnel containing 7.62 pounds of phenylacetone; and (3) 13 plastic jugs containing 104 pounds of lye water with gold oilish rings of phenylacetone on the water’s surface. A chemist for the government, estimated that, taken together, the jugs contained one-half pound of phenylace-tone, 12 which yields one-quarter pound to one-half pound of methamphetamine respectively. 13
1.
The guidelines provide: “Unless otherwise specified, the weight of a controlled substance ... refers to the entire weight of any mixture or substance containing a detectable amount of the controlled substance”. Note following Drug Quantity Table, U.S.S.G. § 2D1.1. Appellants rely on the “market-oriented approach” set forth in
Chapman v. United States,
— U.S. -,
In
Walker,
In short, we are bound by precedent. 16 Accordingly, appellants’ contention that the court erred in considering 103 pounds of lye water fails. 17
2.
Appellants contend that the district court misapplied the drug equivalency tables because it found that the phenylacetone was possessed for the purpose of manufacturing methamphetamine and therefore applied a higher conversion rate. Under U.S.S.G. § 2D1.1, one gram of phenylacetone is equivalent to 2.08 grams of cocaine if possessed “for the purpose of manufacturing methamphetamine”; otherwise, one gram is equivalent to .375 grams of cocaine. Because this issue was not raised in district court, we review for plain error and find none. As stated, see supra, note 15, there is sufficient evidence in the record to support the finding that appellants retained the phenylacetone for the purpose of manufacturing methamphetamine.
C.
Appellants contend that the district court erroneously applied U.S.S.G. § 3Bl.l(b), which provides that “if the defendant was a manager or supervisor (but not an organizer or leader) and the criminal activity involved five or more participants or was otherwise extensive, increase [the offense level] by 3”. Finding that appellants were involved in “a situation involving quite extensive criminal activity”, the district court applied a three level increase for each. In reaching this conclusion, the district court looked beyond the offense of conviction, which was limited to conspiracy to manufacture methamphetamine from approximately March 18 to March 21, and relied on evidence establishing that East-land and Harris were chief participants in a larger multi-state conspiracy to manufacture and distribute methamphetamine; that Eastland recruited Gearhart, who distributed six pounds of methamphetamine over the course of approximately 14 months; and that Harris was the financier of the Eastland organization.
*769
On appeal, appellants do not deny their participation in the larger conspiracy, nor do they maintain that the court erred in its characterization of their role; rather, relying on
United States v. Barbontin,
The conduct underlying the offense of conviction was part of a larger scheme to manufacture and distribute cocaine; accordingly, we conclude that the court correctly applied the guidelines in considering appellants’ conduct in the multi-state conspiracy.
D.
Appellants’ final contention is that the district court erred by use of § 2D1.1(b)(1), which permits a two level increase in the offense level “[i]f a dangerous weapon (including a firearm) was possessed”. Because the decision to apply § 2D1.1(b)(1) is a factual one, we review only for clear error.
United States v. Paulk,
Understandably again seeking a narrow interpretation of the guidelines, appellants’ contend that § 2D 1.1(b)(1) requires possession during the offense of conviction. But this is precisely the contention we rejected in
United States v. Paulk.
There, we held that “[t]he district court could properly consider related relevant conduct in determining the applicability of section 2D1.1(b)(1)”.
We next examine whether the court clearly erred in finding that appellants possessed firearms during the course of their multi-state conspiracy. The commentary to § 2D1.1(b)(1) explains that the enhancement factor “reflects the increased danger of violence when drug traffickers possess weapons”, and should be applied “if the weapon was present, unless it is clearly improbable that the weapon was connected with the offense”. U.S.S.G. § 2D1.1 comment (n.3). Weapon possession is established if the government proves by a preponderance of the evidence “that a temporal and spatial relation existed between the weapon, the drug trafficking activity, and the defendant”.
United States v. Hooten,
1.
Over ten pistols and rifles were discovered in Eastland’s residence the day after his arrest. The majority were found in his bedroom, including a loaded 45 automatic in a nightstand by his bed. (As stated, the weapons had been removed by the time federal agents returned to seize them.) At the sentencing hearing, Brake-field testified that, according to Gearhart, Eastland routinely carried a firearm with him. 20 Intelligence information reported that Eastland dealt methamphetamine out of his house.
The larger conspiracy involved both manufacture and distribution of methamphetamine. Because Eastland dealt from his residence, it became part of the situs of the offense.'
See United States v. McKeever,
2.
Concerning Harris, federal agents discovered four firearms in a trailer on his property in Pike County, Arkansas, two of which were loaded. Also in the trailer was a Merck índex (describes elements used in the manufacture of narcotics), and traces of methamphetamine. In addition, the agents recovered over $200,000, and other drug paraphernalia from the property. In view of the presence of methamphetamine, currency, and paraphernalia, we conclude that the district court did not clearly err in finding that the firearms were connected to the conspiracy to manufacture and distribute methamphetamine.
Harris’s focus on the distance between the laboratory and his residence ignores the fact that the conspiracy under consideration included both manufacture and distribution. Moreover, that the firearms possessed were not the usual firearms or tools of the trade, does not render the court’s findings clearly erroneous. Evidence at trial established that Harris had acquired literature to convert semi-automatic firearms to fully automatic. And, given the evidence indicating the use of his residence in furtherance of the conspiracy, it is, again, “not clearly improbable that the [firearms were] connected to the offense”.
III.
For the foregoing reasons, the judgments of the district court are
AFFIRMED.
Notes
. In 1984, Eastland pleaded guilty to conspiracy to manufacture phenyl-2-propanone, and received a one year sentence. Harris pleaded guilty in 1982 to conspiracy to manufacture phenylacetone, methamphetamine, and amphetamine; he received a four year sentence.
. The agents identified the weapons as follows: a Blackhawk .22 caliber; a Colt 45 automatic; a pistol of unknown brand being .32 or .38 caliber; two Remington model 700; a Weatherby brand .22; a Remington of unknown caliber; a Winchester 30-30 rifle; a Remington .22; an unknown model firearm; a Browning 12-gauge shotgun; and a Smith and Wesson revolver.
.The firearms were described as follows: (1) a .32 caliber Winchester special level action with one expended case and six rounds in the magazine; (2) a Winchester model 75 semi-automatic .22 caliber long rifle; (3) A.M.T. Automag II semi-automatic stainless steel .22 caliber magnum, fully loaded with eight rounds; and (4) a pistola model .27 KAL 7.65 semi-automatic pistol.
. Appellants concede that all observations were made from "open fields”, and not from protected curtilage.
. "The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated." U.S. Const, amend. IV (emphasis added).
. Therefore, we need not reach whether the officers had probable cause, or at least reasonable suspicion, to justify entry.
. At oral argument in March 1993, appellants asserted for the first time that the intrusion implicated the Fourth Amendment because it interfered with possessory interests in property, relying on the recent opinion in
Soldal v. Cook County,
— U.S.-,
. Texas law prohibits trespass, and provides no exception for law enforcement officers. See V.T.C.A. Penal Code § 30.05. Appellants maintain that the deputies’ entry on March 16 constituted an unlawful trespass.
. Appellants also assert that this infringed their right to due process, but do not brief this issue. Accordingly, we do not address it.
. Appellants cite
State v. Hobbs,
. We leave open whether there may be an instance of abuse and/or collusion in which a court might choose to exercise its supervisory powers and exclude evidence obtained in violation of state law.
See Sutherland,
. The chemist explained,
When the process of cleaning up the phenyl-acetone reaction is taking place, the phenylac-etone is placed in a separatory funnel, along with lye water that is the result of the lye here and distilled water. You put those chemicals in here, shake it very vigorously, let it sit for a little while, the phenylacetone will float to the top, lye water is drained off through the spigot at the bottom. Typically its drained into these opaque plastic jugs. As they sit around for a while, or several hours, some of the phenylacetone that was trapped in the lye water will gradually float to the top and form these gold rings.
.Methamphetamine production involves a three step process: (1) production of phenylace-tone; (2) conversion of phenylacetone to methamphetamine oil; and, (3) conversion of the oil to a water soluble salt.
.
See United States v. McKeever,
. The case before us is far more compelling than Ruff, where the solution appeared to be pure waste. Here, because the phenylacetone was capable of producing one-quarter pound to one-half pound of methamphetamine, the district court could easily infer that appellants could use the wash to capture the remaining phenylacetone.
. "In this circuit, one panel may not overrule the decision — right or wrong — of a prior panel, absent en banc reconsideration or a superseding contrary decision of the Supreme Court." In re Dyke, 943 F.2d 1435, 1442 (5th Cir.1991).
., Similarly, Harris's contention that the district court erred in basing his offense level on 47.68 pounds of liquid methamphetamine, because the liquid was not in useable form and contained poisonous by-products, is foreclosed by Fifth Circuit precedent’ cited supra.
. An amendment to the commentary accompanying U.S.S.G. § 3B1.1 clarified whether a court should consider collateral conduct in determining a defendant’s role in the offense. The new introductory comment provides:
The determination of a defendant’s role in the offense is to be made on the basis of all conduct within the scope of § 1B1.3 (Relevant Conduct), i.e. all conduct included under § lB1.3(a)(l)-(4), and not solely on the basis of elements and acts cited in the count of conviction.
U.S.S.G. § 3B1.1 introductory commentary.
.
Mir
reconciled potentially conflicting precedent. In
Barbontin,
.- We reject Eastland’s objection to the admission of this hearsay at his sentencing, hearing. It goes without saying that hearsay is admissible at sentencing.
See Mir,
