In the
 United States Court of Appeals
              For the Seventh Circuit
                       ____________

No. 01-3767
UNITED STATES   OF   AMERICA,
                                           Plaintiff-Appellee,
                             v.

LARRY L. KOERTH a/k/a LONNIE YOUNGER,
                                       Defendant-Appellant.
                       ____________
           Appeal from the United States District Court
              for the Western District of Wisconsin.
       No. 01-CR-52-C-1—Barbara B. Crabb, Chief Judge.
                       ____________
 ARGUED FEBRUARY 13, 2002—DECIDED DECEMBER 5, 2002
                   ____________


  Before COFFEY, MANION and WILLIAMS, Circuit Judges.
   COFFEY, Circuit Judge. Larry L. Koerth appeals the
denial of a motion to suppress evidence seized by police
officers acting under the authority of a facially valid
search warrant issued by a state judge. The district
court found that even though the affidavit was insuf-
ficient to establish the probable cause requirement for
the issuance of a search warrant, the evidence seized was
admissible under the good-faith exception to the ex-
clusionary rule. United States v. Leon, 

(1984).
We affirm.
2                                                   No. 01-3767

                               I.
  On the morning of August 31, 2000, Wisconsin West
Central Drug Task Force1 Investigator Tina Sturz ob-
tained a search warrant from Chippewa County Circuit
Judge Roderick A. Cameron authorizing the search of a
house occupied by Larry L. Koerth and his girlfriend in the
town of Bloomer, Wis. Thereafter, Inv. Sturz and sever-
al other agents entered the residence and seized illegal
weapons, ammunition, and drugs.2 The case was referred
to the federal authorities for prosecution, and subsequent-
ly a federal grand jury returned a two-count indictment
charging Koerth with unlawful possession of controlled
substances, 21 U.S.C. § 841(a)(1), and an assault weapon,
18 U.S.C. § 922(o).
  Before trial Koerth filed a motion to suppress the evi-
dence. The trial judge referred the motion to U.S. Magis-
trate Judge Stephen L. Crocker for review and recom-
mendation. 28 U.S.C. § 636(b). The defendant argued that
the seizure violated the Fourth Amendment because the
agents could not have reasonably believed that the war-
rant was supported by probable cause, notwithstanding
the state judge’s ruling to the contrary. After reviewing
the relevant law and the documents submitted by the de-
fendant with his motion, Magistrate Judge Crocker recom-


1
  The Wisconsin West Central Drug Task Force works together
with the State of Wisconsin Department of Justice’s Division of
Narcotics Enforcement as well as the Chippewa County Sheriff ’s
Department.
2
  Although Special Agent Jay Smith of the State of Wisconsin’s
Division of Narcotics Enforcement did sign an affidavit in support
of a request for a warrant authorizing the arrest of Koerth on
November 9, 2000, and even though the district court did order
the confinement of the defendant pending trial at Dane County
Jail on May 7, 2001, the record does not make clear exactly when
Koerth was taken into custody.
No. 01-3767                                                 3

mended that the defendant’s motion to suppress should
be denied, for despite the judge’s opinion that Sturz’s
affidavit failed to establish probable cause, he found that
the agents reasonably believed that the affidavit was
sufficient to establish probable cause in the officers’ minds.
   The magistrate’s report was filed with the trial judge,
who reviewed the recommendation and findings and is-
sued a 2-page order adopting his recommendations and
denying the motion to suppress. The court ruled that
“although it is the case that the affidavit in support of
the search warrant lacked sufficient facts to establish
probable cause . . . [it] was not so clearly inadequate that
this fact would have been obvious to the officers.” Defen-
dant Koerth thereafter appeared before the trial judge,
entered into a limited plea agreement, and pled guilty
to both of the charges in the indictment—possession of
illegal substances and an assault weapon—with a reser-
vation of the right to appeal the denial of his motion to
suppress. The court accepted the agreement and the guilty
plea, received testimony and found the defendant guilty
as charged, and sentenced him to 71 months in prison
followed by a three-year term of supervised release.


                             II.
  We defer to the warrant-issuing judge’s initial determina-
tion of probable cause if “there is substantial evidence
in the record supporting the judge’s decision.” United
States v. Lloyd, 

, 1262 (7th Cir. 1995). We
apply the clear error standard of review to any addition-
al factual findings or credibility determinations made by
the district judge based upon affidavits and/or testimony
received during a suppression hearing, and apply the
de novo standard of review to the federal court’s ulti-
mate legal conclusion of whether a law enforcement officer
reasonably relied upon a subsequently invalidated search
4                                             No. 01-3767

warrant. See United States v. Spry, 

, 834-35
(7th Cir. 1999); United States v. Adames, 

, 747
(7th Cir. 1995).


                           III.
                            A.
  The issue is whether the trial court committed error
when it denied the motion to suppress the evidence seized.
Unless “the magistrate or judge in issuing a warrant
was misled by information in an affidavit that the affiant
knew was false or would have known was false except
for his reckless disregard of the truth,” we will suppress
evidence obtained pursuant to a facially valid warrant
issued by a neutral, detached magistrate only if: (1) the
warrant is later invalidated; and (2) the police could not
have relied in objective good faith upon the neutral and
detached magistrate’s decision to issue the warrant. See

, 923.
  When there is a genuine dispute about whether a police
officer could have reasonably relied in good faith upon
a state judge’s decision to issue a search warrant, review-
ing courts are encouraged to consider this threshold
question first: Did the affidavit provide the magistrate
with a “substantial basis” to rule that there was probable
cause? Illinois v. Gates, 

, 238 (1983). If the
question is answered in the affirmative, then it follows
that the officer’s actions were reasonable. On the other
hand, if this question is answered in the negative, then
we must ascertain the answer to the question: Could the
officer have reasonably believed that the facts set forth
in the affidavit were sufficient to support a magistrate’s
finding of probable cause? See United States v. Leon,

, 920-24 (1984); see also United States v.
Danhauer, 

, 1005-07 (10th Cir. 2000); United
No. 01-3767                                                5

States v. Dahlman, 

, 1397-98 (10th Cir. 1993).
By resolving the issue of probable cause before addressing
the question of good-faith reliance, we further the Leon
Court’s goal of establishing legal principles that will serve
to “guide future action by law enforcement officers and
magistrates” who review, issue, and apply for warrants.

.


                             B.
  When, as here, the affidavit is the only evidence pre-
sented to the warrant-issuing magistrate, “the warrant
must stand or fall solely on the contents of the affidavit.”
United States v. Roth, 

, 509 (7th Cir. 1967).
In the case before us, the name of the informant was
undisclosed and the issuing magistrate was not pre-
sented with any live testimony. Thus, “the task of the
issuing magistrate is simply to make a practical, common-
sense decision whether, given all the circumstances set
forth in the affidavit before him, including the ‘veracity’
and ‘basis of knowledge’ of persons supplying hearsay
information, there is a fair probability that contraband
or evidence of a crime will be found in a particular place.”

. “And the duty of a reviewing court
is simply to ensure that the magistrate had a ‘substantial
basis for concluding’ that probable cause existed.” 

must examine the totality of the circum-
stances to determine whether the affidavit on its face
established probable cause. Where the affidavit is sup-
ported by an informant’s tip, the totality-of-the-circum-
stances inquiry encompasses several factors, including:
(1) the extent to which the police have corroborated the
informant’s statements; (2) the degree to which the in-
formant has acquired knowledge of the events through
firsthand observation; (3) the amount of detail provided;
and (4) the interval between the date of the events and
6                                               No. 01-3767

police officer’s application for the search warrant. United
States v. Jones, 

, 609 (7th Cir. 2000); 

; United States v. Lamon, 

, 1187-
88 (7th Cir. 1991). The court should also consider wheth-
er the informant personally appeared and presented an
affidavit or testified before the magistrate, thus allowing
the judge to evaluate the informant’s knowledge, demean-
or, and sincerity. United States v. Reddrick, 

,
1281 (7th Cir. 1996).
  The magistrate judge’s decision to issue a warrant “is
to be given considerable weight” and should be overruled
only when the supporting affidavit, read as a whole in a
realistic and common sense manner, fails to allege spe-
cific facts and circumstances to allow the judge to rea-
sonably conclude that the items sought to be seized are
associated with the crime and located in the place indi-
cated. 

(internal quotations omitted).
It is well-established that appellate courts may not uphold
a warrant issued based solely on conclusory allegations.
“Even if the warrant application was supported by more
than a ‘bare bones’ affidavit, a reviewing court may prop-
erly conclude that, notwithstanding the deference that
magistrates deserve, the warrant was invalid because
the magistrate’s probable-cause determination reflected
an improper analysis of the totality of the circumstances
or because the form of the warrant was improper in some
respect.” 

(internal citation omitted).
  The Government concedes that Inv. Sturz’s affidavit
failed to establish a substantial basis for concluding that
there was probable cause to search Koerth’s house. (Br.
at 23.) Inv. Sturz’s affidavit reads as follows:
    On Wednesday, Aug. 30, 2000, a search warrant was
    executed at 806 Ruff Pl., Bloomer, Wis., which led
    to the seizure of marijuana, methamphetamine, and
    U.S. Currency. Investigation revealed that the mari-
No. 01-3767                                               7

    juana and methamphetamine were purchased from a
    white male, known as Lonnie, who resides at 2344
    195th Ave.
    Abraham Savage, who is believed to be a reliable
    source, indicated that he was at Lonnie’s on Thursday,
    Aug. 29, 2000, and witnessed a large amount of mari-
    juana. Savage stated he believed there was approxi-
    mately 150-200 pounds of marijuana at the residence,
    as well as approximately two pounds of methamphet-
    amine, a large bag of cocaine, and $30,000 in U.S.
    currency.
    Savage has purchased from Lonnie in the past and
    that [sic] Lonnie is a member of the Iron Wings Motor-
    cycle Club. Savage has also seen numerous firearms
    in the residence to include [sic] fully automatic weap-
    ons. Savage also indicated that Lonnie “would not
    be afraid to shoot” and that “law enforcement would
    have to shoot it out with him.”
    Based on concern for officer and citizen safety, affiant
    requests a “no knock” provision.
    /s/ Tina Sturz
The Sturz affidavit presented the magistrate judge with
little more than mere conclusions and assertions of
wrongdoing on the part of the defendant, without an
adequate factual foundation, based on the testimony of
a previously unknown informant. We therefore accept
the Government’s concession, for we are convinced that
the affidavit failed to sufficiently support the search war-
rant executed by Sturz.
  Another attack made on the contents of the affidavit
focuses on the credibility of the informant. Initially, the
affidavit fails to explain the extent, if any, that Savage
has previously provided information leading to arrests
or prosecutions for criminal activity of any kind. Even
8                                              No. 01-3767

assuming the affidavit’s conclusory statement that Savage
“is believed to be a reliable source,” our cases hold that
such characterizations, standing alone without any sup-
porting factual information, merit absolutely no weight
and that “information obtained from ‘a reliable source’ ”
must be treated “as information obtained from an inform-
ant of ‘unknown reliability.’ ” United States v. Brack, 

, 755 (7th Cir. 1999).
   Statements from an informant of unknown reliability
may in certain instances serve to establish probable cause
if, under the totality of the circumstances, a reasonable
person might consider that the statements are worthy of
credence. 

. In this particular case,
the Government agrees that the officers failed to present
sufficient evidence tending to convince us that Savage
was a reliable informant. Furthermore, for reasons unex-
plained, the officers did not see fit to present Savage
to testify in person before the warrant-issuing judge, de-
spite the fact that Savage was available and being held
in custody at the county jail. While “it is possible that
weak factual information may be bolstered if the author-
ities undertake probative efforts to corroborate an infor-
mant’s claims,” United States v. Weaver, 

, 1379
(6th Cir. 1996), Inv. Sturz failed to provide the magistrate
judge with information stating what steps, if any, were
taken to corroborate his statements contained in the war-
rant application.
  To uphold the state judge’s ruling in this case would be
to ratify the search of a home based on the use of essen-
tially conclusory statements without corroboration. Al-
though the task force agents are to be commended for
ferreting out and apprehending the defendant in this
case, we refuse to water down the probable cause stan-
dard in the name of fighting crime. Due to the lack of the
necessary quantum of reliable information, we hold that
the warrant was invalid. See 

;
No. 01-3767                                                9

United States v. Fairchild, 

, 263-64 (7th Cir.
1991); United States v. Brown, 

, 993-94 (7th
Cir. 1987); United States v. McNeal, 

,
951-60 (S.D. Ind. 2000). Nevertheless, we refuse to sup-
press the evidence seized, for we are convinced that De-
fendant-Appellant Koerth failed to rebut the Govern-
ment’s prima facie case establishing that the officers acted
in good faith and reasonably believed that they had ful-
filled the probable cause requirement necessary to obtain
a search warrant.


                             C.
  If a defendant is successful in establishing the invalidity
of the search warrant, the burden then shifts to the Gov-
ernment to establish that the police relied in good faith
on the judge’s decision to accept the affidavit and issue
the warrant. See 

. An officer’s decision
to obtain a warrant is prima facie evidence that he or
she was acting in good faith. See 

n.21; 

(White, J., concurring); see also 

; 

. Two ways
that the defendant may rebut this prima facie case are
by presenting evidence to establish either that: (1) the
magistrate “wholly abandoned his judicial role,” or other-
wise failed in his duty to “perform his ‘neutral and de-
tached’ function and not serve merely as a rubber stamp
for the police”; 

, 914; or (2) the offi-
cer submitted an affidavit “so lacking in indicia of prob-
able cause as to render official belief in its existence
entirely unreasonable.” 

  In attempting to rebut the Government’s prima facie
case of good-faith reliance, Koerth initially argues that
the trial judge merely rubber-stamped the warrant pre-
sented to him. An officer may not rely upon a search
warrant if he is aware or had reason to believe that the
10                                               No. 01-3767

magistrate improperly issued the warrant without mean-
ingfully and critically evaluating the evidence presented
at the probable cause hearing. See, e.g., Stewart v. State,

(Ark. 1986). Cf. 

;
United States v. Breckenridge, 

, 1321 (5th Cir.
1986). Although we have difficulty understanding how a
defendant can establish that the trial judge acted as a
rubber stamp in the absence of evidence detailing the
impropriety or inadequacy of the warrant application
proceedings as well as the type of interaction (or lack
thereof) between the judge and the officers. It is interest-
ing to note that Defendant Koerth advised the magistrate
that he was willing to have his suppression motion decided
without the benefit of a formal evidentiary hearing. (Tr. at
3-6.) Koerth failed to submit a shred of evidence (such as
an affidavit, police record, or deposition transcript) to sub-
stantiate his bold and speculative accusation that the
state magistrate “neither read or reviewed the affidavit,
nor engaged in any dialogue with Inv. Sturz before the
warrant was signed.” (Br. at 13.) Based upon the totality
of the information presented, including our review of the
record, we are convinced that the judge complied with
the requirement of acting as a neutral and detached
magistrate by giving careful consideration to Inv. Sturz’s
warrant application.
  The remaining issue, then, is whether the affidavit
presented to the judge was “so lacking in indicia of prob-
able cause,” 

, that no officer could
have “harbored an objectively reasonable belief” to the
contrary. 

In order to determine whether an
officer could have relied in objective good faith on the
magistrate’s decision to issue a search warrant, we limit
our inquiry to whether the officer could have reasonably
believed that the materials presented to the magistrate
judge (either in an affidavit or in some other respect such
as testimony from the police officers) were sufficient to
No. 01-3767                                               11

establish probable cause. See 

& n.13,
923 n.23; United States v. Bynum, 

, 210-13 (4th
Cir. 2002) (Michael, J., dissenting); United States v. Wil-
helm, 

, 121-22 (4th Cir. 1996); United States v.
Baker, 

, 1149-50 (10th Cir. 1990); United
States v. Hove, 

, 140 (9th Cir. 1988).
   We evaluate an officer’s good-faith reliance with an
analysis similar to that used in cases involving the af-
firmative defense of qualified immunity. See Olson v. Tyler,

, 1120 (7th Cir. 1987) (citing Malley v. Briggs,

(1986)). “Police officers in effecting searches
are charged with a knowledge of well-established legal
principles as well as an ability to apply the facts of a
particular situation to these principles.” 

. When evidence has been obtained pursuant to a
subsequently invalidated search warrant, we will exercise
our discretion and admit the evidence only if we are
convinced, after review, it is appropriate to do so pursu-
ant to Leon’s exception to the exclusionary rule. That is
to say, we will admit the evidence unless: (1) courts have
clearly held that a materially similar affidavit previously
failed to establish probable cause under facts that were
indistinguishable from those presented in the case at
hand; or (2) the affidavit is so plainly deficient that any
reasonably well-trained officer “would have known that
his affidavit failed to establish probable cause and that
he should not have applied for the warrant.” 

. See also Hope v. Pelzer, 

, 2515-16
(2002); Anderson v. Creighton, 

, 640 (1987).
  We are convinced that Inv. Sturz acted in objective good
faith, and the evidence seized by the drug task force was
properly admitted, because it was not clearly established
on August 31, 2000 that Inv. Sturz’s affidavit failed to
justify a search of Defendant Koerth’s house. We explained
in Part III.B that it was clearly established prior to Au-
gust 31, 2000 that an officer seeking to obtain a search
12                                              No. 01-3767

warrant was required to provide more than an uncorrob-
orated, conclusory assertion of illegal activity from a con-
fidential informant of unknown reliability. However, Koerth
has failed to provide us with any cases holding that an
affidavit materially similar to Inv. Sturz’s would fail to
meet the test of establishing probable cause based upon
information from a named informant like Savage. Savage
had first-hand knowledge of a criminal suspect’s alleged
illegal activity and his testimony arguably included state-
ments against his penal interest even though that testi-
mony was presented in a conclusory and essentially un-
corroborated fashion. Based on the evidence presented
in the absence of such a ruling, we refuse to hold that Inv.
Sturz behaved unreasonably, or acted in objective bad
faith, or disregarded clearly established law when conduct-
ing her investigation and relying upon the search warrant
issued in the case before us. See Humphrey v. Staszak, 

, 727 (7th Cir. 1998).
  Inv. Sturz’s affidavit does contain some indicia of illegal
drug dealing at the house on 195th Place, Bloomer, Wis. A
practical, common-sense reading of the affidavit presented
reveals that Savage had purchased drugs from Koerth on
prior occasions, the most recent of which was within 56
hours of the issuance of the warrant. On this prior occasion,
Savage visited the house on 195th Place and observed a
large quantity of marijuana, methamphetamine, and co-
caine along with fully automatic weapons and what he
estimated to be $30,000 in currency, thereby implying
that Koerth was engaged in ongoing acts of drug trading
from the house. As we said in Perry:
     [T]he factfinder was certainly entitled to infer, using
     his God given gift of common sense, that [the defen-
     dant] knew of the substantial drug transaction taking
     place. Judges in the federal system, whether they are
     in the trial or appellate system, do not operate in a
No. 01-3767                                                13

    vacuum, shielded from knowledge of drug operations
    in the real world of the 1980’s.
United States v. Perry, 

, 1169 (7th Cir.
1984).
  It is “beyond dispute that drug traffickers are often armed
and dangerous,” United States v. Ocampo, 

,
1369 (7th Cir. 1989), and it is well-known that “[i]n the
case of drug dealers, evidence is likely to be found where
the dealers live.” 

. Thus, it should
be clear that Savage’s statements provided the type of
facts that, if corroborated or explained in greater detail,
might very well have been sufficient to establish probable
cause. See 

  Furthermore, Savage’s statements to the investigating
officer referred to in the affidavit on file in this case were
made on August 30, 2000, almost immediately after police
searched his home and found him in the possession of
drugs and other illicit substances which he stated he had
just recently purchased from Koerth (within 56 hours
prior to August 30, 2000). One inference that the state
magistrate judge could have drawn was that Savage, in an
attempt to strike a bargain with the police, had a strong
incentive to provide accurate and specific information
rather than false information about Koerth’s illegal activity.
See United States v. Leidner, 

, 1429-30 (7th
Cir. 1996); State v. Ward, 

, 524 (Wis. 2001).
But cf. 2 LaFave, Search & Seizure § 3.3(c) at 131 (1996).
  Unlike the confidential (undisclosed) informants in the
cases cited by the defendant, Savage’s identity was made
known to the magistrate judge at the probable cause
hearing. Though an anonymous tip “alone seldom demon-
strates the informant’s basis of knowledge or veracity,”
Alabama v. White, 

, 329 (1990), a magistrate
in the exercise of sound judgment is entitled to give great-
er weight to a tip from a known informant, who can be
14                                                No. 01-3767

held responsible should he be found to have given mis-
leading information to police officers, and thus has an
incentive to provide truthful information to the detectives.
See Florida v. J.L., 

, 270 (2000); Adams v.
Williams, 

, 146-47 (1972); see also WIS. STAT.
§ 946.41 (prohibiting the filing of false reports with a po-
lice officer). For these reasons and others set forth herein,
we hold that the judge acted within his discretion when
deciding to give greater weight to the information gained
from Savage rather than from some anonymous inform-
ant, considering that the police found Savage in posses-
sion of a quantity of illegal drugs and he identified Koerth
contemporaneously, at the same time of his arrest. See
Webb v. Lane, 

, 394 (7th Cir. 1991); Gross v.
Greer, 

, 120 (7th Cir. 1985).
  As a final matter, because the probable-cause determina-
tion is based solely on the information presented during
the warrant application process, we note that the district
judge properly refused to consider documents that were
not presented to warrant-issuing Judge Cameron and
were cited by the Government for the first time at the
suppression hearing in federal court. (Doc. 23 at 13.) As
courts have previously stated:
     The Leon test for good faith reliance is clearly an
     objective one and it is based solely on facts presented to
     the magistrate. An obviously deficient affidavit can-
     not be cured by an officer’s later testimony on his
     subjective intentions or knowledge. . . . Leon creates an
     exception to the exclusionary rule when officers have
     acted in reasonable reliance on the ruling of a judge
     or magistrate. The point is that officers who present
     a colorable showing of probable cause to a judicial
     officer ought to be able to rely on that officer’s ruling
     in executing the warrant. When the officers have not
     presented a colorable showing . . . the reasoning of Leon
     does not apply.
No. 01-3767                                              15

(internal citations omitted). See also

(Michael, J., dissenting) (“In sum,
the Government cannot establish an officer’s objective
good faith under Leon by producing evidence of facts
known to the officer but not disclosed to the magistrate.”);

.


                   IV. CONCLUSION
  Inv. Sturz obtained the warrant to search Defendant
Koerth’s house on August 31, 2000. We are unaware of
any cases decided prior to that date, nor have any been
cited to us by the defendant, where a federal court sup-
pressed evidence in a case involving an affidavit with
materially similar factual recitations as the one before us,
where the officers provided a magistrate with indicia of
probable cause based on information from a named infor-
mant making statements almost contemporaneous with
his arrest, which were based on personal knowledge and
determined to have been against the informant’s penal
interest. Although Savage’s affidavit lacks the detail or
corroboration necessary to establish probable cause, the
affidavit does make clear that Savage had repeatedly
purchased drugs from Koerth on previous occasions, in-
cluding a purchase within the previous 56 hours, at which
time Savage had the opportunity and did observe a large
quantity of the same drugs, which he estimated to be
150-200 pounds of marijuana, two pounds of methamphet-
amine, and a bag of cocaine, along with illegal weapons
and an unusually large amount of cash at Koerth’s resi-
dence. We are convinced that it was objectively reasonable
for Inv. Sturz to rely in good faith upon the state trial
judge’s decision to issue the warrant to search the defen-
dant’s residence for drugs and drug-related paraphernalia.
We hold that the district judge properly denied Larry L.
Koerth’s motion to suppress the evidence based upon the
16                                             No. 01-3767

good-faith exception set forth in United States v. Leon, 

(1984).
  The judgment of the district court is AFFIRMED.

A true Copy:
      Teste:

                        ________________________________
                        Clerk of the United States Court of
                          Appeals for the Seventh Circuit




                   USCA-02-C-0072—12-5-02