OPINION OF THE COURT
GARTH, Circuit Judge:
We are called upon to determine whether a letter written by the plaintiff Reginald Carter, a prison inmate, violated the Federal Rules of Evidence when it was read and admitted into evidence at the trial of a § 1983 action brought by Carter against prison authorities. We determine that it did not, and therefore affirm the judgment of the district court in favor of the defendants.
I.
Reginald Carter is an inmate at the Pennsylvania State Correctional Institution at Huntingdon. He claims that he was severely beaten in the course of a routine “shakedown,” or search, of his cell on September 22, 1977 by three prison guards, defendants John Fuiek, Duane Pyles, and Gilbert Levi. On the date of the incident, Carter was housed in Huntingdon’s maximum security block as a result of his role in an escape attempt a week earlier in which a guard was seriously injured. Carter brought suit against the three guards and against Lowell Hewitt, superintendent of the prison, under 42 U.S.C. § 1983.
The defendants moved to dismiss the complaint, or, in the alternative, for summary judgment. Supporting affidavits were filed with their motion. The action was referred to a U.S. Magistrate under 28 [964]*964U.S.C. § 636 (1976). The Magistrate directed Carter to file responsive affidavits, but Carter claimed that he was unable to do so due to the restrictions he was subject to as a maximum security prisoner. Faced with this circumstance, the Magistrate scheduled an evidentiary hearing at the prison, at which time Carter’s factual contentions were fully tried.
At the hearing, conducted without a jury on July 24, 1978, Carter presented three witnesses and also testified himself. The three witnesses were inmates housed in cells adjacent to or near Carter’s at the time of the alleged beating. They all testified that Fuiek, Pyles, and Levi, the three defendant guards, came to Carter’s cell shortly after 2:00 in the afternoon of September 22,1977, ordered him out of the cell, and proceeded to beat him with batons, flashlights, fists, and feet. They all testified that they could not actually see the beating, due to the restricted visibility from their cells, but that they could hear the blows being landed. Two testified that they never noticed any bruises on Carter as a result of the beating; one testified that he noticed some swelling of Carter’s face.
Carter testified to the beating in greater detail. He stated that he was hit on the head three or four times with a flashlight and hit 30-35 times with a baton. He also claimed he was kneed in the face, causing his mouth to bleed. He testified, however, that the only visible signs of the beating as early as a day or two later were a swollen lip and some bruises on the back of his neck; all other injuries, he claimed, were covered by his clothes.
The defense called as witnesses the three defendant guards. They testified that they went to Carter’s cell on the day in question for a routine shakedown. Fuiek entered the cell, ordered Carter out, and commenced the search. When Carter left the cell, he grabbed Officer Levi’s baton and a struggle ensued. Pyles tried to pull Carter off Levi. Fuiek heard the commotion, left the cell, and demanded that Carter release the baton with the words, “turn it loose or I’ll run this [flashlight] through your face.” Carter then released the baton, and Fuiek completed his search. All three guards claimed that Carter had not been hit by anyone in any way.
The defense also put in the testimony of prison infirmary supervisor Morgan, that Carter would have shown more extensive injuries if he had been beaten as badly as he claimed, or in the manner that he described.
The incident giving rise to this appeal occurred during Carter’s cross-examination. Carter was shown a letter written by one “Abdullah” to a fellow inmate at Hunting-don. Carter admitted that he had written the letter, and also admitted that he had denied writing this same letter when he had been questioned as to its authorship in an earlier prison disciplinary proceeding. Defense counsel asked Carter to read the letter. Carter objected on the grounds of relevance, claiming that the letter had been written six months after the alleged beating. The Magistrate then ordered Carter to read the letter but expressly reserved ruling on whether the letter was admissible. Complying with the Magistrate’s direction, Carter read the letter aloud. The letter, which was undated, generally described to its unidentified recipient how to file a complaint charging prison guard brutality.1 In [965]*965its most significant portion, the lettef reads:
This is a set up my brother — compile complaints to be use for bullshit courts, possibly news media, and a radio program in Pittsburg [sic] & W.D.A.S. down Philly. We want to establish a pattern of barbaric brutal harrassment [s/c] and turn it on these chumps to the max.
Defense counsel suggested that this letter was a direction to file a false brutality complaint. Carter claimed that he was only encouraging the filing of a legitimate complaint.
Shortly after the hearing, the Magistrate submitted proposed findings of fact and conclusions of law to the district court. Resolving the matter that had been expressly reserved, the Magistrate admitted the letter in evidence as reflecting on Carter’s credibility and demonstrating a modus operandi on Carter’s part of filing false brutality complaints. Relying in part on the letter, the Magistrate recommended that the district court find that no beating had occurred and that judgment be entered in favor of the defendant guards. As to Superintendent Hewitt, the Magistrate recommended that his motion for summary judgment be granted since Carter had neither alleged nor proved that Hewitt had directed or encouraged the beating in any way. The district court adopted the Magistrate’s recommendations2 and entered judgment for the defendants.3
[966]*966Carter now appeals, challenging admission of the letter on three grounds. First, he claims that the letter constitutes character evidence rendered inadmissible by F.R.Evid. 404. Second, he claims that the letter is extrinsic evidence used to prove bad acts to impeach his credibility, and is therefore inadmissible under F.R.Evid. 608(b). Finally, he contends that, even if otherwise admissible, the letter should have been excluded under F.R.Evid. 403 because “its probative value is substantially outweighed by the danger of unfair prejudice.” 4
The defendants meet none of these contentions in their brief. Rather, in what we must regard as a questionable litigation strategy, they do not argue that the letter is admissible; they argue, instead, that even if admission of the letter constituted error, the error was harmless. If the letter was inadmissible, as Carter contends, we would find it difficult to hold that its admission was harmless. Both the Magistrate and the district court expressly relied, and relied heavily, on the letter in their opinions. Since, however, on our own analysis, we cannot agree with Carter that the letter was inadmissible, we do not reach the defendants’ claim that any such error was harmless.
We consider, and reject, each of the three grounds of inadmissibility raised by Carter, in turn.
II.
A. The Rule 404 Claim
We believe, quite simply, that the letter is admissible, substantive evidence because it bears on the central factual issue in the case — whether Carter was beaten by prison guards on September 22, 1977. The standard of relevance established by the Federal Rules of Evidence is not high: evidence is relevant if it has “any tendency to make the existence of any fact that is of consequence to determination of the action more probable or less probable than it would be without the evidence.” F.R.Evid. 401 (emphasis added). A factfinder could reasonably interpret this letter as reflecting a plan on Carter’s part to promote the filing of false complaints. A factfinder could further draw the inference that Carter’s own complaint about being beaten on September 22, 1977 had been filed pursuant to that plan. Thus, the letter is relevant: it has some tendency to make Carter’s assertion that he was beaten less likely to be true than it would be without the evidence. Since the letter is relevant, it is also admissible, unless its admission is otherwise restricted. F.R.Evid. 402.
Carter claims, however, that F.R. Evid. 404(b) constitutes a restriction on admissibility. This rule provides:
(b) Other crimes, wrongs, or acts. Evidence of other crimes, wrongs, or acts is [967]*967not admissible to prove the character of a person in order to show that he acted in conformity therewith. It may, however, be admissible for other purposes, such as proof of motive, opportunity, intent, preparation, plan, knowledge, identity, or absence of mistake or accident.
Carter claims that before evidence of his act, solicitation of a false complaint, may be admitted under this rule to prove a plan of filing false complaints, there must be much greater similarity between the action solicited in his letter (the filing of a false complaint) and the action taken by Carter (the filing of a complaint charging the defendants with beating Carter on September 22, 1977). We cannot agree; his contention misconstrues both the nature of the evidence introduced and the rule itself.
Federal Rule of Evidence 404(b), in this context, governs attempts to prove the existence of a plan through evidence of a series of acts that conform to the plan. Thus, the rule would be implicated here if the defendants, merely by showing that Carter had filed false brutality complaints on several other occasions, thereby sought to prove that Carter had conceived and implemented a plan of filing such false complaints. This letter does not, however, serve that purpose. Rather, Carter’s letter constitutes direct evidence of the existence of a plan, in its statement that “[t]his is a set up my brother .... We want to establish a pattern of barbaric brutal har-rassment [sic] and turn it on these chumps to the max.”
The difference is critical, and may be demonstrated by a simple example. Assume Carter’s letter had stated, instead of its actual content, that “I think we can put these prison guards on the defensive by establishing a pattern of prison guard harassment. I intend doing so by encouraging prisoners to file numerous false complaints against the guards. Pursuant to this plan, I filed a false complaint of a beating by three guards on September 22, 1977.” It could not be claimed that rule 404 would require such evidence to be in the form of proof of a series of discrete false complaints, and that in the absence of such proof the letter was inadmissible. And if we add to this hypothetical letter a request to the recipient to file a false complaint himself, it could not be claimed that rule 404 would demand great similarity between the complaint solicited and the complaint filed earlier by the author, before the letter could be admitted into evidence. The reason is clear. In the typical case of proof of a plan under the rule, the trier of fact is asked to infer the existence of the plan merely from proof of a series of similar acts. In such a case, the effectiveness of the proof of a plan depends wholly on the similarity of the acts shown.
By contrast, however, in the hypothetical letter described above and in Carter’s actual letter, there is direct evidence of the existence of the plan; the letters are strong evidence of a plan even if there is no proof of any complaint filed by the author other than the one at issue in the case, and even if the recipient of the letter is not asked to file a false complaint. Since, these letters prove the plans directly and not inferentially, they fall outside the scope of rule 404: the letters are not evidence of other acts used as indirect proof of a plan, but direct evidence of the existence of the plan itself.5 When there is direct evidence of a plan, admissibility does not depend on proof of a series of highly similar acts. Therefore, Carter’s letter must be deemed admissible. [968]*968If the hypothetical letters described above are admissible, as surely they are, then so is Carter’s; the differences among them go only to probative weight, not admissibility. While some inferences, no doubt, must be drawn from Carter’s letter to reach the conclusion that he had a plan of filing false complaints and encouraging others to do so, and that the complaint about the incident of September 22,1977 was part of this plan, these inferences only render the letter less probative, not less admissible. See United States v. Ravich, 421 F.2d 1196, 1204 n.10 (2d Cir.) (Friendly, J.), cert. denied, 400 U.S. 834, 91 S.Ct. 69, 27 L.Ed.2d 66 (1970).
Even assuming, however, that rule 404 governs the admissibility of the letter, and that Carter’s letter falls within rather than without, the scope of the rule, Carter misconstrues the rule’s similarity requirement. In those cases demanding striking similarities between the act in question and the acts sought to be proved as evidence of a pattern, the issue is the identity of the perpetrator of the act (generally crime) in question. The typical context is that defendant Jones is charged with crime X, and the prosecution offers evidence of crimes Y and Z, which Jones concedes committing. The prosecution then asks the trier of fact to infer that since crime X is so peculiarly similar to crimes Y and Z, it must have been Jones who committed crime X. See, e. g., United States v. Goodwin, 492 F.2d 1141, 1154 (5th Cir. 1974); Drew v. United States, 118 U.S.App.D.C. 11,16, 331 F.2d 85, 90 (D.C.Cir.1964).6 When the issue is identity, it is perfectly proper and, indeed, necessary, to exclude other act evidence unless “it bears such a high degree of similarity as to mark it as the handiwork of the accused.” United States v. Goodwin, 492 F.2d at 1154. But identity is not an issue in this case; Carter concedes that he both wrote the letter and filed the complaint about the September 22, 1977 beating. The issue is rather what light the letter sheds on Carter’s brutality complaint. There is no fear, as in the identity cases, that the factfinder may draw an erroneous conclusion as to the identity of the person who committed a crime or performed an act. There is no need, then, for the “striking similarity” required in the identity cases, and little reason to hesitate to place this evidence before the trier of fact to draw all appropriate inferences.7 The limitation of the “striking similarity” requirement to cases in which identity is the issue is well made in United States v. Myers, 550 F.2d 1036 (5th Cir. 1977). The court there stated:
The government asserts that the evidence of the Pennsylvania bank robbery was admissible to prove that Myers committed the Florida bank robbery because it exhibits his characteristic modus oper-andi. This is a proper purpose. The probity of evidence of other crimes where introduced for this purpose depends upon both the uniqueness of the modus operan-di and the degree of similarity between the charged crime and the uncharged crime. Of course, it is not necessary that the charged crime and the other crimes be identical in every detail. But they must possess a common feature or features that make it very likely that the unknown perpetrator of the charged crime and the known perpetrator of the uncharged crime are the same person. The more unique each of the common features is, the smaller the number that is required for the probative value of the evidence to be significant. But a number of common features of lesser uniqueness, although insufficient to generate a strong inference of identity if considered sepa[969]*969rately, may be of significant probative value when considered together. . . .
A much greater degree of similarity between the charged crime and the uncharged crime is required when the evidence of the other crime is introduced to prove identity than when it is introduced to prove a state of mind. We have consistently held that for evidence of other crimes to be admissible the inference of identity flowing from it must be extremely strong.
Id. at 1045 (footnotes and citations omitted). See United States v. Powell, 587 F.2d 443, 448 (9th Cir. 1978).
We reject, then, Carter’s contention that there was insufficient similarity between the complaint that he solicited in the letter and the complaint that he filed, to allow admission of the letter under rule 404. We hold that the letter was properly admissible as substantive evidence.
B. The Rule 608(b) Claim
The Magistrate and the district court found the letter admissible in part because it bore on Carter’s credibility in testifying that he had suffered a beating at the hands of the defendants. Carter claims this use of the letter violates the limitations on impeachment set forth in F.R.Evid. 608(b). We disagree.
Rule 608(b) provides:
(b) Specific instances of conduct. Specific instances of the conduct of a witness, for the purpose of attacking or supporting his credibility, other than conviction of crime as provided in rule 609, may not be proved by extrinsic evidence. They may, however, in the discretion of the court, if probative of truthfulness or untruthfulness, be inquired into on cross-examination of the witness (1) concerning his character for truthfulness or untruthfulness, or (2) concerning the character for truthfulness or untruthfulness of another witness as to which character the witness being cross-examined has testified.
The principal concern of the rule is to prohibit impeachment of a witness through extrinsic evidence of his bad acts when this evidence is to be introduced by calling other witnesses to testify. Thus, Weinstein and Berger describe the extrinsic evidence ban as follows:
Courts often summarize the no extrinsic evidence rule by stating that “the examiner must take his [the witness’s] answer.” This phrase is descriptive of federal practice in the sense that the cross-examiner cannot call other witnesses to prove the misconduct after the witness’ denial; it is misleading insofar as it suggests that the cross-examiner cannot continue pressing for an admission — a procedure specifically authorized by the second sentence of Rule 608(b).
3 J. Weinstein & M. Berger, Weinstein’s Evidence ¶ 608[05], at 608-22 (1978) (footnote omitted).
Similarly, McCormick writes:8
In jurisdictions which permit character-impeachment by proof of misconduct for which no conviction has been had, an important curb is the accepted rule that proof is limited to what can be brought out on cross-examination. Thus, if the witness stands his ground and denies the alleged misconduct, the examiner must “take his answer,” not that he may not further cross-examine to extract an admission, but in the sense that he may not call other witnesses to prove the discrediting acts.
E. Cleary, McCormick on Evidence § 42, at 84 (2d ed. 1972) (footnotes omitted).
Thus, the great majority of the decisions finding violations of rule 608(b) do so when the extrinsic evidence that is chal[970]*970lenged is obtained from a witness other than the one whose credibility is under attack. When, however, the extrinsic evidence is obtained from and through examination of the very witness whose credibility is under attack, as is the case here, we must recognize that the rule’s core concerns are not implicated. There is, however, an even more significant reason for finding no violation of the extrinsic evidence rule here: Carter did not deny having written the letter; rather, he conceded his authorship but claimed that the letter was not an effort to encourage the filing of false complaints.
Carter’s adoption of the letter, and thus his admission of the act used to impeach him, distinguishes this case from every case where the witness, whose credibility is under attack, has denied the evidence which had been obtained from or through him, thus leading to a holding that the extrinsic evidence rule has been violated. In those cases, the witness has denied, rather than admitted, the acts used to impeach him. The impeachment process thus would have required the examiner to produce additional evidence to refute the witness’s denial of the acts charged. Such a process makes apparent the basis for the rule against extrinsic evidence: if refutation of the witness’s denial were permitted through extrinsic evidence, these collateral matters would assume a prominence at trial out of proportion to their significance. In such cases, then, extrinsic evidence may not be used to refute the denial, even if this evidence might be obtained from the very witness sought to be impeached. But, as we have observed, Carter’s ease does not present such a situation.
The impeaching letter with which Carter was confronted was not met by a denial of his authorship. Carter’s admission that he wrote the letter distinguishes this case from all cases relied on by him. Carter relies especially heavily on United States v. Herzberg, 558 F.2d 1219 (5th Cir.), cert. denied, 434 U.S. 930, 98 S.Ct. 417, 54 L.Ed.2d 290 (1977). In Herzberg, two defendants were convicted of using the mails in a scheme to defraud. On cross-examination, the prosecutor asked one of the defendants, Barnes, if any fraud litigation had arisen out of a business relationship he had had with a Mrs. Vosack. In response to Barnes’s denial, the prosecutor showed Barnes the opinion of the Arizona Supreme Court in a suit brought by Mrs. Vosack against him and others, and asked him to read aloud the last sentence of the opinion. This sentence revealed that the court was affirming a decision below that Barnes had defrauded Vosack. The court held that this line of questioning violated the extrinsic evidence ban of rule 608(b). 558 F.2d at 1222-23.
Thus, the Herzberg court found rule 608(b) violated only when the evidence was introduced after Barnes denied his bad act. Every other case in which the extrinsic evidence ban has been found violated by evidence brought forth during cross-examination of the witness under attack likewise fits this pattern. In each case, the extrinsic evidence was employed after a denial by the witness under attack of the specific instances of conduct. See, e.g., United States v. Turquitt, 557 F.2d 464 (5th Cir. 1977); United States v. Dinitz, 538 F.2d 1214 (5th Cir. 1976), cert. denied, 429 U.S. 1104, 97 S.Ct. 1133, 51 L.Ed.2d 556 (1977); Carlsen v. Javurek, 526 F.2d 202 (8th Cir. 1975).9
[971]*971The sole case analogous to this one, i. e., in which the challenged witness did not clearly deny the alleged instances of conduct, found no violation of rule 608(b) when documentary proof of those instances was introduced during questioning of the witness. In United States v. Senak, 527 F.2d 129 (7th Cir. 1975), cert. denied, 425 U.S. 907, 96 S.Ct. 1500, 47 L.Ed.2d 758 (1976),10 an attorney was charged with unlawfully soliciting payment from clients whom he had been assigned to represent in his position of public defender. On cross-examination, the prosecution asked Senak whether he had reported a certain fee on his income tax return. He responded that, if his return did not disclose the fee, then it was solely through neglect rather than intentional wrongdoing. The prosecution then introduced into evidence Senak’s IRS records, which revealed that the fee had not been reported.
Senak claimed that this cross-examination violated rule 608(b), but his contention was rejected. While the court’s reasoning is not perfectly clear, it concludes that the introduction of the records did not constitute proof of specific instances of conduct through extrinsic evidence, but merely inquiry into such conduct on cross-examination, which is permitted by the rule. See 527 F.2d at 145. Thus, no violation of rule 608(b) was found even though the IRS records were utilized and admitted as extrinsic evidence.
The distinction noted here between our case and those cases in which the extrinsic evidence ban was found to be violated by evidence brought forth during cross-examination of the witness under attack— that Carter admitted the conduct charged while all other witnesses denied it — provides a sound basis for allowing admission of Carter’s letter. The purpose of rule 608(b)’s extrinsic evidence ban, as noted, is “to avoid minitrials on wholly collateral matters which tend to distract and confuse the jury.” United States v. Simmons, 444 F.Supp. 500, 507 (ED.Pa.1978). Wigmore similarly describes the rationale behind the common law ban on extrinsic evidence: to prevent confusion of issues through proliferation of testimony on minor matters; and to prevent unfair surprise arising from false allegations of improper conduct. 3A Wigmore on Evidence § 979, at 826-27 (Chadbourn rev. ed. 1970). These reasons for barring extrinsic evidence lose their force when the witness whose credibility is challenged concedes the alleged acts. No issues are confused or time wasted through a trial of a collateral matter: no trial is needed since the matter is conceded. The trial judge may exercise control over the degree to which the conceded matters are explored through his power to bar irrelevant or cumulative evidence. F.R.Evid. 402, 403. Nor is there any danger of unfair surprise through false charges of bad conduct. If the witness concedes the matter, we may be confident that the charges were not false.
Thus, there is no need in such a case to invoke rule 608(b)’s ban on extrinsic evidence, particularly where, as here, credibility is the critical issue.11 We conclude, [972]*972then, that the use of Carter’s letter for impeachment purposes on cross-examination, and its admission, did not offend rule 608(b).12
C. The Rale 403 Claim
Carter finally contends that the letter should have been excluded under F.R.Evid. 403. Again, we are constrained to disagree.
Rule 403 provides:
Although relevant, evidence may be excluded if its probative value is substantially outweighed by the danger of unfair prejudice, confusion of the issues, or misleading the jury, or by considerations of undue delay, waste of time, or needless presentation of cumulative evidence.
This rule cannot help Carter. It does not offer protection against evidence that is merely prejudicial, in the sense of being detrimental to a party’s case. Rather, the rule only protects against evidence that is unfairly prejudicial. Evidence is unfairly prejudicial only if it has “an undue tendency to suggest decision on an improper basis, commonly, though not necessarily, an emotional one.” Advisory Committee’s Note, F.R.Evid. 403. It is unfairly prejudicial if it “appeals to the jury’s sympathies, arouses its sense of horror, provokes its instinct to punish,” or otherwise “may cause a jury to base its decision on something other than the established propositions in the case.” 13 1 J. Weinstein & M. Berger, Weinstein’s Evidence ¶ 403[03], at 403-15 to 403-17 (1978). A classic example of unfair prejudice is a jury’s conclusion, after hearing a recitation of a defendant’s prior criminal record, that, since the defendant committed so many other crimes, he must have committed this one too. This is an improper basis of decision, and the law accordingly prohibits introduction of prior convictions to demonstrate a propensity to commit crime. F.R.Evid. 404.14
Carter’s letter, while undoubtedly prejudicial to his case in that it resulted in the district court ruling against him, presents no danger of unfair prejudice. The letter was offered by the defendants to suggest that no beating occurred on September 22, 1977 and that Carter was lying when he testified to the contrary. This, of course, was the central issue at trial. In a case such as the one here where the witnesses on each side take diametrically op[973]*973posed positions, the factfinder’s task is to determine which witnesses are more credible. If the Magistrate, after hearing the letter read, drew the inference that Carter was lying, it cannot be claimed that this was an improper basis of decision. It was, rather, a use of properly admitted evidence which, together with other evidence in the case, resulted in a decision on a proper basis. Thus, Carter has made no showing of unfair prejudice: he cannot demand exclusion of the letter under rule 403.15
III.
Because the dissenting opinion largely addresses subjects which we do not find relevant to our disposition, we feel obliged to record our observations on these matters. The dissent apparently takes no real issue with any aspect of the analysis set forth in part II, above, but notes only that: “Although I do not discuss in detail the several theories on which the majority finds the letter admissible, my silence should not be construed as acquiescence.” At 977. Yet, our reading of the dissent reveals to us that, in fact, there is no disagreement with our holding that the letter is admissible. It is conceded by the dissent that its own hypothetical letter, set forth in its opinion at page 977, is admissible. Yet the differences between the dissent’s hypothetical letter and Carter’s real one, like the differences between our hypothetical letter and the actual one, go only to probative weight, not admissibility.
The main thrust of the dissent does no more than urge a reversal of the district court on a ground not raised. Essentially, the dissent’s point is that the Magistrate erred in not allowing Carter to call as a witness the individual to whom the letter was addressed. Our review of the record compels us to disagree.
When Carter was presented with the letter during his cross-examination, and before he was directed to read it, Carter objected to the letter’s relevance. It was at that time, and that time only, that Carter asked to call the recipient as a witness. Recognizing the potential validity of Carter’s relevance objection, the Magistrate at that time denied Carter’s request, since the letter had neither been admitted in evidence nor read aloud by Carter. The Magistrate stated: “I don’t think his [the recipient’s] statements will be particularly relevant and I’m not certain at this juncture, Mr. Carter, that this document is relevant.” After extensive discussion of the letter during Carter’s cross-examination, in which its relevance was made clear, the Magistrate then asked Carter whether he wished to make any other statement. Carter responded “No.” Neither at this time nor at any other time did Carter ever renew his request to call the recipient of the letter. Under these circumstances, then, it is clear that Carter’s failure to call his witness to explain the meaning of the letter cannot be charged to the court.
In not renewing his request, it may be that Carter recognized what our reading of the record reveals: that no innocent interpretation of the letter is plausible. When questioned by the Magistrate as to the significance of the statement in the letter that “[t]his is a set up my brother .... We want to establish a pattern of barbaric brutal harrassment [sic],” Carter himself could only offer the patently questionable explanation that it referred to a “set-up” of inmates by the guards (tr. at 70).
IV.
We conclude that all three grounds urged by Carter on this appeal, whereby he would have us hold that the district court erred in considering his letter as a matter of evidence, are without merit. We will therefore affirm the October 31, 1978 judgment entered for the defendants and against Carter. Costs will be taxed against the appellant Carter.