201 F.3d 900 (7th Cir. 2000)
United States of America,    Plaintiff-Appellee,v.Charles Kroledge, Kathleen Kroledge  a/k/a Kathy Kroledge, Tony L. Kroledge  and Ethel Juanita Kroledge,    Defendants-Appellants.
Nos. 99-1338, 99-1339, 99-1340 & 99-2164
In the  United States Court of Appeals  For the Seventh Circuit

Appeal from the United States District Court  for the Northern District of Indiana, Hammond Division.  No. 96 CR 33--James T. Moody, Judge.
Argued November 4, 1999Decided January 7, 2000
[Copyrighted Material Omitted]
Before Manion, Kanne and Evans, Circuit Judges.
Kanne, Circuit Judge.


1
Charles Kroledge, his wife  Kathleen Kroledge, Charles's brother Tony  Kroledge and Tony's wife Ethel Juanita Kroledge  were convicted on December 1, 1997, of conspiracy  to participate in mail fraud. Ethel and Kathleen  Kroledge were also convicted of mail fraud. The  Kroledges' convictions resulted from the family's  attempt to defraud its insurer by filing false  claims in conjunction with a fire, allegedly set  by Charles Kroledge, that damaged Charles and  Kathleen's home. The four were indicted on the  charge of using fire to commit a felony, but all  were acquitted.


2
The Kroledges do not appeal the merits of their  convictions. Instead, they contend that their  sentences were wrongly enhanced, because the  district court included the arson as relevant  conduct for purposes of enhancing each of their  offense levels, and ask us to reconsider the  standard of evidence required to include  acquitted offensesas relevant conduct for the  purpose of sentence enhancement. They also claim  that the district court erred in enhancing their  sentences for obstruction of justice. Finding no  errors, we affirm.

I.  History

3
In May 1991, one of Charles and Kathleen  Kroledge's children accidentally shot a hole in  the family's television, causing it to spark.  This accident led Charles's brother Gilbert to  joke that Charles and Kathleen, who were under  considerable financial pressure to keep up with  the mortgage payments on their house, would be  better off if the house did catch fire. These  events allegedly spawned a plan in Charles's mind  to burn down the house and use the insurance  money to build a new house for the family.  Shortly thereafter, Charles and Kathleen sought  Gilbert and his wife Martha's help in planning  the fire, and the four engaged in activities such  as experimenting with ways to start a fire and  packing up mementoes, photographs and records.  Charles's brother Tony and his wife Ethel also  became involved as Charles and Kathleen stored  some of the boxes containing their possessions at  Tony and Ethel's house.


4
On the morning of June 8, 1991, Charles told  Martha that he and his wife intended to set fire  to the house that night and that they would spend  the evening with Tony and Ethel at the stock car  races while the house burned. Sometime after 1:00  a.m. that night, the Hobart, Indiana fire  department responded to a fire at Charles and  Kathleen Kroledge's home. Although members of the  Hobart Fire Department considered some of the  damage to the house suspicious and worthy of  arson investigation, the house was actually  located in the jurisdiction of the neighboring  town of Lake State, Indiana. Therefore, the Lake  Station Fire Department was responsible for the  investigation.


5
Lake Station's fire investigator Ken Corbeille  who was inexperienced in arson investigation,  focused on an electrical outlet rather than on  other damage and determined that the fire was  accidental. Corbeille then left the fire scene  unattended for several hours. During this time,  Gilbert Kroledge testified at trial that he and  Tony Kroledge removed newspapers from inside the  walls and among the furniture cushions of the  couch where the fire started. These newspapers  were allegedly planted by Charles to provide  trailer for the fire.


6
Charles and Kathleen Kroledge declared that  their entire house and all their valuables  (including those that they had stored with Tony  and Ethel) had been destroyed by the fire. In  addition, Kathleen and Ethel Kroledge forged  false receipts for an apartment where Charles and  Kathleen were supposedly residing during the  reconstruction of their house. Ethel Kroledge  asked the owner of the apartment that Kathleen  claimed to be renting, Annette Mathews, whether  she could use Mathews's name on insurance claim  forms and told Mathews to lie if anyone asked  whether Kathleen and Charles were living with  her. During this time, Charles, Kathleen and  their family were actually living with Tony and  Ethel Kroledge. When the fire was declared an  accident, their insurer, State Farm Insurance  Company ("State Farm"), reimbursed Charles and  Kathleen for both their loss and their living  expenses.


7
In October 1991, Martha and Kathleen Kroledge  had a falling out because Kathleen informed  Martha's husband Gilbert of an affair that Martha  was having. Martha was enraged by this and told  a relative about Charles and Kathleen's  activities. This relative contacted State Farm's  fraud investigators, who in turn contacted the  FBI. The FBI contacted Martha, and the agency  granted Martha and Gilbert immunity from  prosecution in exchange for their cooperation in  the investigation of the fire.


8
In August 1993, an FBI investigator spoke with  Charles and Kathleen Kroledge about the events  surrounding the 1991 fire.Charles and Kathleen  told this investigator that they attended stock  car races that night and did not return home  until 1:00 a.m. In November 1993, the same  investigator spoke to Tony and Ethel Kroledge  about their involvement in the fire. Neither Tony  nor Ethel mentioned that Charles and Kathleen  stayed with them during the time that the  Kroledges were rebuilding their house, but the  two did verify that Charles and Kathleen had  attended stock car races with them on the night  of the fire.


9
During the 1993 investigation, Martha and  Gilbert Kroledge secretly tape recorded  conversations with Charles, Tony and Ethel. These  conversations implicated each of the Kroledges in  the scheme to defraud the insurer. Charles  admitted that he burned his own house down. Tony  and Ethel admitted that they had stored many of  Charles and Kathleen's possessions for them.


10
On April 10, 1996, the four Kroledges--Charles,  Kathleen, Tony and Ethel--were indicted on  charges of conspiracy to commit mail fraud, mail  fraud (on three counts) and using fire or an  explosive to commit a federal felony. All four  pleaded not guilty. After the return of a  superseding indictment substituting certain  mailings for which the mail fraud allegations  would be based, trial commenced on November 17,  1997.


11
At trial, Charles Kroledge denied even  discussing the possibility of starting a fire at  his house. He also denied experimenting with ways  to start a fire, and he testified that he  attended stock car races on the night that the  fire occurred. Kathleen admitted that she may  have misrepresented her loss in her claim to  State Farm but testified that she and Charles did  not have financial problems. She denied lying to  a State Farm investigator who asked her where she  was living during the reconstruction of her  house. State Farm claims adjuster Bob Bradley  contradicted Kathleen's story, claiming that  Kathleen never informed him that she was living  with Tony and Ethel. In addition, Annette Mathews  testified that Ethel told her to tell any person  who asked that the Kroledges were living in her  apartment.


12
Ethel Kroledge testified that she told the FBI  investigator that she had lied about where  Charles and Kathleen had lived during the  rebuilding process, but the FBI investigator  testified that she never admitted her lie prior  to her testimony before a grand jury in 1994.  Tony testified that he had no idea who lived in  his house in 1991 because he worked nights. He  also testified that Charles and Kathleen were  with Tony at the stock car races on the night  that the fire took place.


13
The jury found all four Kroledges guilty of  conspiracy to commit mail fraud. The jury also  found Kathleen Kroledge guilty of two counts of  mail fraud and Ethel Kroledge guilty of one  count. The jury acquitted the Kroledges of all  remaining counts, including using fire to commit  a federal felony. At sentencing, however, the  court found by a preponderance of the evidence  that the Kroledges used fire as a part of their  conspiracy to defraud State Farm, and therefore,  the court used evidence of the arson as relevant  conduct and applied this conduct to each  defendant's sentence. This evidence of relevant  conduct led to a two-point enhancement of each  defendant's base offense level for reckless risk  of serious bodily injury and another two-point  enhancement for more than minimal planning. In  addition, the court found that Tony, Kathleen and  Charles had each obstructed justice by providing  false testimony and lying to FBI investigators  about their role in the conspiracy. Because of  medical problems that she experienced, Ethel was  separately sentenced. At her separate sentencing,  the district court adopted the same findings  about her behavior except that the court made no  finding of perjury, and she was given a similar  sentence. Charles, Tony and Ethel Kroledge were  each sentenced to twenty-seven months  imprisonment with a three year term of supervised  release.Kathleen Kroledge was sentenced to  thirty-three months imprisonment with a three  year term of supervised release. Each of the  defendants was ordered to pay State Farm  $78,344.85 in restitution.

II.  Analysis

14
The Kroledges challenge the enhancement of their  sentences on three grounds. First, they claim  that the district court erred in enhancing each  of their sentences for obstruction of justice.  Second, they claim that the district court lacked  sufficient evidence of arson to include it as  relevant conduct for purposes of calculating  their sentences. Third, they argue that the  district court applied the wrong evidentiary  standard in determining whether to include the  arson as relevant conduct for the purpose of  computing each of their sentences.


15
Both the challenge to the district court's  enhancement to the Kroledges' sentences for  obstruction of justice and the challenge to the  court's inclusion of arson as relevant conduct  are determinations made for the purpose of  sentencing. We review sentence determinations for  clear error. See United States v. Gwiazdzinski,  141 F.3d 784, 788 (7th Cir. 1998). We will  reverse on clear error only if we are left with  a definite and firm conviction that a mistake has  been committed. See United States v. Garcia, 69  F.3d 810, 819 (7th Cir. 1995).

A.  Obstruction of Justice

16
Each of the Kroledges challenges the enhancement  of his or her sentence for obstruction of  justice. Sentencing Guidelines sec. 3C1.1  authorizes a two-point enhancement for  obstruction of justice if the sentencing court  finds by a preponderance of the evidence that a  defendant "willfully obstructed or impeded . . .  the administration of justice during the course  of the investigation, prosecution, or sentencing  of the instant offense." U.S. Sentencing  Guidelines Manual sec. 3C1.1 (1997). "To  establish an obstruction of justice, the  sentencing court must make an independent factual  finding that the defendant engaged in a willful  attempt to provide false testimony." United  States v. Smith, 103 F.3d 600, 606 (7th Cir.  1996) (citation omitted). When a defendant  objects to an enhancement for obstruction of  justice, the district court must review the  evidence and make an independent determination as  to the existence of the willful obstruction of  justice. See United States v. Menting, 166 F.3d  923, 929 (7th Cir. 1999). Since the court based  its finding of obstruction against each Kroledge  on different facts, we review each finding  independently.

1.  Charles Kroledge

17
The sentencing court based its finding of  obstruction of justice against Charles Kroledge,  among numerous other items, on his testimony that  Tony and Ethel Kroledge had no involvement in the  scheme to defraud State Farm. Charles claims that  this finding, which was based on the pre-sentence  report, was inaccurate and did not meet the  required specificity for findings of fact as to  the willfulness and materiality of Charles's  testimony. We disagree.


18
Even if the district court did not explicitly  address the willful and material nature of  Charles's testimony, we may uphold the  enhancement as long as the district court made a  finding of obstruction that "encompasses all of  the factual predicates for a finding of perjury."  United States v. Craig, 178 F.3d 891, 901 (7th  Cir. 1999) (quoting United States v. Dunnigan,  507 U.S. 87, 95 (1993)). Charles's testimony  regarding Tony and Ethel Kroledge's involvement  in the conspiracy speaks to the guilt of  Charles's co-conspirators, Tony and Ethel, and is  therefore a material obstruction. See Craig, 178  F.3d at 901. Thus, to enhance Charles's sentence  for obstruction, Charles's inaccurate testimony  must have been made willfully, rather than as a  result of mistake, faulty memory orconfusion.  See Craig, 178 F.3d at 901. An enhancement  authorized by sec. 3C1.1 may employ a defendant's  perjurious testimony, but we construe the  Guidelines in such a way as to avoid punishing  defendants for exercising their right to testify.  See Dunnigan, 507 U.S. at 96; United States v.  Emerson, 128 F.3d 557, 563 (7th Cir. 1997). In  this instance, we find that the court correctly  met this standard by focusing on elements of  Charles's testimony that did not reflect directly  on his own guilt or innocence.


19
Charles testified that no one, including Tony,  entered the house after the arson investigator  left the premises. This statement seems to have  been made with the intent to show that his  brother Tony had no participation in his scheme.  However, Gilbert Kroledge testified that he and  Tony Kroledge entered Charles's house after the  arson investigator left and removed newspaper  from the couch and walls. Rather than claiming  that his statements at trial were mistaken or the  result of confusion, he still claims that his  statements do not suggest that Tony and Ethel  were not involved in the case. Because his  statements were made to exculpate his family, we  find no error in the court's determination that  Charles's testimony formed the basis for a  finding of obstruction.

2.  Kathleen Kroledge

20
The district court based its finding of  obstruction against Kathleen Kroledge on her  testimony that Tony and Ethel Kroledge were not  involved in the conspiracy. The court found that  she obstructed justice both by her trial  testimony and by pretrial statements that she  made to investigators. In her opening statement,  Kathleen Kroledge confessed lying to  investigators when she and Charles misrepresented  their living expenses to State Farm. She now  claims that her earlier false statements were  immaterial and the finding that she perjured  herself at trial was inaccurate.


21
Kathleen Kroledge testified at trial that she  told State Farm's claim adjuster that she was  staying with Tony and Ethel, rather than at an  apartment as she had claimed. She also testified  that she was often away from Tony and Ethel's  house, so Tony might not have been aware that she  and Charles were living there. State Farm's claim  adjuster Bob Bradley testified that Kathleen  never informed him that Charles and Kathleen's  family were residing with Tony and Ethel after  the fire. In addition, Tony Kroledge testified  that he told FBI investigators that he knew  Charles and Kathleen Kroledge were living with  his family while they rebuilt their house.


22
Kathleen Kroledge's testimony contradicts  statements that she made to State Farm and to the  FBI prior to trial and contradicts itself in  several places. Given the testimony of the  government's witnesses at trial, we find that the  trial court had sufficient evidence to conclude  that the statements by Kathleen about Tony's  knowledge of her family's presence in their home,  as well as many other contradictory statements,  constituted an attempt to obstruct justice, and  we will not second guess the district court on  such questions of credibility. Kathleen's  statements were material, as they would tend to  influence the decisionmaking body to which they  were addressed. See United States v. Wells, 519  U.S. 482, 483 (1997). Therefore, we find that the  district court's finding was accurate on the  ground of her perjurious testimony and that its  enhancement must be upheld without regard to the  materiality of her earlier false statements.

3.  Tony Kroledge

23
The district court enhanced Tony Kroledge's  sentence because he provided an alibi for his  brother and sister-in-law. Tony Kroledge argues  that this finding was in error because any  misstatements that he made to investigators  occurred early in the investigation and were  thereforeimmaterial. Application Note 6 to  Sentencing Guidelines sec. 3C1.1 defines  materiality as "evidence . . . that, if believed,  would tend to influence or affect the issue under   determination." U.S. Sentencing Guidelines Manual  sec. 3C1.1 application note 6. Although  misstatements made to investigators that do not  force investigators to expend additional  resources are not material, see United States v.  Barnett, 939 F.2d 405, 407 (7th Cir. 1991),  pretrial statements that significantly obstruct  or impede an investigation are material and may  serve as the basis for an enhancement. See id.


24
Tony Kroledge provided an alibi for his brother  and sister-in-law by testifying that the two  accompanied him to the stock car races on the  night of the fire. Further, he corroborated  Charles's claim that Charles and Kathleen  followed him home that night and did not find out  about the fire until after 1:00 a.m. However, his  own testimony and the testimony of some  government witnesses suggest discrepancies in his  story. Gilbert and Martha Kroledge both testified  that they saw Charles and Kathleen Kroledge  driving in the direction of the races on the  night of the fire at an hour when Tony testified  they were already with him. Tony Kroledge  testified that it generally took thirty-five to  forty minutes to return to his home from the  races, yet he testified that on the night of the  fire it took the Kroledges well over an hour to  return home. In addition, Tony Kroledge testified  on direct examination that he told the FBI  investigator that Charles and Kathleen lived with  him during the rebuilding of their home, but he  also testified that he did not know at the time  that they were living with him. Under cross-  examination, Tony Kroledge admitted that he never  told anyone that Charles and Kathleen lived with  him until he testified so under oath before the  grand jury.


25
On appeal, Tony Kroledge explains, through  counsel, that these statements were mistakes made  by a simple man confused by the proceedings who  was attempting only to protect his family.  However, the district court found instead that  these statements were made willfully in an  attempt to obstruct justice. We review such  findings of credibility with great deference and  will not reverse unless we find clear error. See  United States v. Hall, 101 F.3d 1174, 1179 (7th  Cir. 1996). As such, the obstruction enhancement  to Tony Kroledge's sentence will remain  undisturbed.

4.  Ethel Kroledge

26
The district court enhanced Ethel Kroledge's  sentence for obstruction of justice, but, unlike  her co-defendants, the court based its  enhancement on Ethel Kroledge's pretrial conduct  rather than her testimony. On appeal, Ethel  Kroledge argues that her pretrial conduct did not  significantly impede the government's  investigation into the fire and, therefore, was  not material for the purposes of enhancing her  sentence for obstruction.


27
In its finding that Ethel Kroledge obstructed  justice, the court adopted the finding of fact  contained in the pre-sentencing report that Ethel  Kroledge had obstructed justice by attempting to  influence the testimony of a witness. Ethel  Kroledge admitted in her testimony that she told  FBI investigators that Charles and Kathleen lived  with Annette Mathews during the period when their  house was being rebuilt. Annette Mathews  testified that Ethel Kroledge asked her to lie to  the FBI and State Farm investigators and claim  that Charles and Martha lived in their basement  apartment during that period. Ethel Kroledge  admitted that she asked Annette Mathews whether  she could use her name on receipts that the  Kroledges presented to State Farm.


28
The presented testimony dispels any argument  that Ethel Kroledge did not obstruct justice in  an attempt to protect her brother and sister-in-  law. However, she claims that her misstatements  were not material because she later corrected  them by telling the truth to FBI investigators.To determine the materiality of her conduct, we  must review whether the district court correctly  found that Ethel Kroledge's actions significantly  impeded the investigation of the Kroledges'  conduct. See Barnett, 939 F.2d at 407. In  Barnett, we refused to uphold an enhancement for  obstruction of justice based on a defendant's  pretrial conduct when the defendant's only  pretrial misstatement was that he denied  committing the offenses about which he was  questioned. See id.; see also United States v.  Wells, 154 F.3d 412, 414 (7th Cir. 1998) (stating  that obstruction of justice that "has no  consequence . . . is not a permissible basis" for  enhancement).


29
In this case, however, Ethel Kroledge's  misstatements went well beyond a mere declaration  of innocence. Instead, Ethel Kroledge concocted  a false set of facts that led investigators  toward a witness whom she had attempted to  influence. As in Wells, Ethel Kroledge attempted  to lead investigators on a "wild goose chase" in  order to obscure evidence of her own criminal  conduct. However, in this instance, unlike Wells,  the evidence that Ethel Kroledge would obscure  was not merely ancillary to questions of her (and  her family's) guilt; the activities she concealed  were exactly those which led to Kathleen  Kroledge's and her own convictions for mail  fraud. In circumstances such as these, we have  found that such behavior was material, see United  States v. Taylor, 135 F.3d 478, 483-84 (7th Cir.  1998), and we have no question that Ethel  Kroledge's behavior significantly impeded the  instant investigation. As such, her behavior was  material for the purpose of determining whether  her sentence should be enhanced for obstruction,  and we will uphold the district court's  enhancement of her sentence.

B.  Use of Arson as Relevant Conduct

30
The Kroledges also argue that the district  court erred when it found by a preponderance of  the evidence that they had committed arson and  that this arson could be used as relevant conduct  for the purpose of computing their sentence. They  argue that the district court lacked sufficient  evidence to determine by a preponderance of the  evidence that they committed arson, and in the  alternative, they argue that under these  circumstances the more rigorous "clear and  convincing evidence" standard should have been  applied instead of the "preponderance of the  evidence" standard.


31
All four Kroledges were acquitted of the  federal crime of arson--using fire in the  furtherance of a federal felony. However, the  district court determined, for the purposes of  sentencing, that a preponderance of the evidence  indicated that the Kroledges had committed arson,  and the court decided to use the acquitted  offense of arson as relevant conduct for the  computation of their sentences. In United States  v. Watts, 519 U.S. 148, 149 (1997), the Supreme  Court held that acquitted offenses may be used as  relevant conduct for the purposes of computing a  defendant's sentence. The decision in Watts  confirmed our own prior precedent, see United  States v. Fonner, 920 F.2d 1330, 1332 (7th Cir.  1990), which allowed such conduct to be taken  into account. See Watts, 519 U.S. at 149.


32
Sentencing judges may use all information that  they possess in order to properly compute their  sentence. See 18 U.S.C. sec. 3661 ("No limitation  shall be placed on the information concerning the  background, character, and conduct of a person .  . . for the purpose of imposing an appropriate  sentence."). Because the relevant burden at  sentencing is the "preponderance of the  evidence," we allow evidence of acquitted conduct  to be considered as long as the government has  met the burden of proving by a preponderance of  the evidence that defendants have engaged in the  relevant conduct, see United States v. Porter, 23  F.3d 1274, 1277-78 (7th Cir. 1994), rather than  applying the more stringent standard "beyond a  reasonable doubt" required to convict a  defendant.See Fonner, 920 F.2d at 1333. Thus, we  will uphold the sentences imposed by the district  court whenever we determine that the government  at trial met the applicable standard for proving  that the defendants have engaged in the relevant  conduct even if they were acquitted at trial  under the stricter standard.

1.  Relevant Burden of Proof

33
We have held that a preponderance of the  evidence is all that is required under the  Sentencing Guidelines for a finding of fact. See,  e.g., Porter, 23 F.3d at 1277. Despite our clear  precedent, the Kroledges urge us to consider the  argument that a heightened standard of proof must  be met under some instances "where a factual  finding will result in a sentencing increase so  great 'that the sentencing hearing can fairly be  characterized as a tail which wags the dog of the  substantive offense.'" United States v. Corbin,  998 F.2d 1377, 1387 (7th Cir. 1993) (citations  omitted). In support, the Kroledges cite United  States v. Kikumura, 918 F.2d 1084, 1102 (3d Cir.  1990), in which the Third Circuit required the  higher standard of proof in a case where the  sentencing court raised the defendant's sentence  from about thirty months to thirty years.


34
In Corbin, we acknowledged the possibility that  a higher standard might be appropriate in those  circumstances where the government appeared to  use the sentencing hearing to retry the  substantive offense. In such circumstances, the  district court might use its discretion to depart  from the Sentencing Guidelines in such a way as  to effectively sentence a defendant to the term  that would have been appropriate had she been  convicted of the substantive offense. As we noted  in United States v. Rodriguez, 67 F.3d 1312, 1322  (7th Cir. 1995), we have not yet been presented  with an opportunity to consider whether, under a  certain set of facts, such a heightened standard  of proof may be appropriate. We are confident  that these facts do not merit the imposition of  the clear and convincing evidence standard.


35
Here, the Kroledges were each acquitted of the  charge of use of fire in the furtherance of a  federal felony, pursuant to 18 U.S.C. sec.  844(i), which provides that any person who  "maliciously damages or destroys . . . by means  of fire or an explosive, any building, vehicle,  or other real or personal property . . . shall be  imprisoned for not less than 5 years and not more  than 20 years." Thus, if the Kroledges had been  convicted of the federal arson charge, they would  each serve between five and twenty years.  Instead, by enhancing their sentences based on  the relevant conduct of arson, each Kroledge is  serving either twenty-seven or thirty-three  months, which is roughly half of the minimum  sentence that they would have received for the  arson charge. As we noted in Porter, see 23 F.3d  at 1277-78, we have in many instances refused to  adopt the Kikumura standard in cases where the  sentence enhancement was more drastic than the  enhancement at issue here. See Rodriguez, 67 F.3d  at 1323 (51-63 months enhanced to life  imprisonment); Porter, 23 F.3d at 1276 (92-115  months enhanced to 137 months); United States v.  Masters, 978 F.2d 281, 283-85 (7th Cir. 1992)  (33-41 months enhanced to 40 years). Contrasting  these cases with the facts of Kikumura, we find  that this does not qualify as a rare instance  where a higher standard might be justified.

2.  Sufficiency of the Evidence

36
The Kroledges also argue that, even under the  preponderance of the evidence standard, the  sentencing court lacked sufficient evidence of  the arson to include it as relevant conduct for  the purpose of enhancing their sentences. Because  there is ample evidence available in the record  on which to base a finding of arson, we  understand this claim actually to imply that the  district court committed clear error by believing  the government's witnesses and disbelieving the  Kroledges' witnesses.


37
Determinations of credibility by the sentencing  judge are entitled to great deference on review.  See United States v. Anaya, 32 F.3d 308, 314 (7th  Cir. 1994). When confronted with conflicting  testimony, sentencing judges "are fully capable  of considering the motivations of witnesses in  weighing conflicting evidence and, because they  have had an opportunity to assess the demeanor of  the witnesses, are in a better position than this  court to make credibility determinations." United  States v. Griffin, 115 F.3d 1322, 1331 (7th Cir.  1997). For this reason, when a defendant asks  only that we reassess a credibility  determination, the argument is "wasted on an  appellate court," United States v. House, 110  F.3d 1281, 1286 (7th Cir. 1997) (citation  omitted), unless a challenged witness's testimony  is shown to be inconsistent with contemporary  documents or impossible. See, e.g., United States  v. Grandinetti, 891 F.2d 1302, 1307 (7th Cir.  1989).


38
In this case, the Kroledges do not challenge  any evidence presented by the government.  Instead, they argue that the government's  evidence should not outweigh the evidence that  the Kroledges presented. The government's  evidence of arson included testimony of at least  three witnesses, each of whom told a consistent  story, as well as such physical evidence as  Charles and Kathleen Kroledge's possessions pre-  dating the fire, which had been stored with their  family to preserve them, and the tape recordings  made by Gilbert Kroledge, which capture  admissions made by the Kroledges about the nature  of the fire. We consider this evidence sufficient  to support the district court's determination.

III.  Conclusion

39
We find that the sentencing court correctly  enhanced Charles, Kathleen, Tony and Ethel  Kroledge's sentences for obstruction of justice.  In addition, we find that the district court's  decision to include the arson that the Kroledges  were accused of committing as relevant conduct  for the purpose of computing their sentences was  correctly based on a preponderance of the  evidence. Therefore, we AFFIRM the decisions of the  district court

