Brown was found guilty by a jury of the armed robbery of Mario Barber and a related firearm offense. Barber was the sole eyewitness to the alleged robbery. In
Brown v. United States,
*535
We are constrained to hold that the trial court abused its discretion in excluding the proposed cross-examination. Despite a proffer supporting a good faith belief by the defense that Barber fabricated the account of the robbery to conceal his purchase of drugs that evening, the trial court prohibited any cross-examination whatsoever designed to suggest this theory of bias. We conclude that this total exclusion of questioning could not be justified by any obligation on the court’s part to balance the probative versus prejudicial value of the proffered evidence. And because we also are unable to conclude that the erroneous prohibition of the questioning was harmless error,
see Brown, 1,
FACTUAL SUMMARY
The underlying facts leading to Brown’s conviction were set forth in
Brown I, supra,
[W]hat happened on ... [the] night of this alleged robbery is that it was not a robbery at all, but that it ... was an incident where Mario Barber was seeking to buy drugs, specifically marijuana. And that in the course of that transaction, there was a disagreement between Mario Barber and the person or persons from whom he was attempting to buy the drugs. And during that dispute, the shotgun was discharged and he was shot by someone other than Rocky Brown. And that Mr. Barber’s motive to fabricate in this situation was specifically that he did not want to reveal to law enforcement authorities what he really was doing on Georgia Avenue that evening because that activity was illegal and therefore he made up, fabricated the story that he had been robbed.
Brown’s counsel stated that this proffer was “based on what I consider to be reliable, privileged information,” specifically, “firsthand information ... from somebody who was on the scene.” The proffer was further supported, counsel asserted, by the evidentiary contradictions at trial between Barber’s testimony that his wallet and jacket had been taken in the robbery and the fact that his wallet was found at the scene and his jacket was seen to be in his possession later that night. Finally, counsel claimed support for the proposed questioning in Barber’s “irrational version of events and how things happened, and how he went from one place to another and tricked these robbers even though they were so bent on robbing him ....” 2
ANALYSIS
As we explained in
Brown I,
Barber was cross-examined at trial about his possible motive to fabricate the robbery in order to gain favor with the government, and so avoid prosecution, for a scheme to defraud his former employer that was being investigated at the time of trial.
Brown I,
We agree with Brown that he made the necessary showing of a good faith belief to support that questioning. Indeed, the trial court ultimately did not disagree with that conclusion. As we discuss later, the court barred the questioning on the ground that, notwithstanding an adequate proffer, the probative value of the questions on the issue of bias was outweighed by their potential to distract and inflame the jury with degrading evidence of drug use by Barber. Along the way, however, the judge made a distinction that requires examination. The court determined that, since the source of the proffer was “someone who was on the scene,” Brown’s counsel “had a good faith basis for believing that [Barber] may have been trying to buy marijuana.” Nevertheless, the court reasoned that what might have begun as an attempt to buy drugs by Barber could still have ended up in a robbery of him by Brown and others, and so the proffer of facts suggesting an attempted drug purchase did not “translate ... into” a good faith belief that Barber had a motive to fabricate the robbery. This distinction seems to us very doubtful. Although an attempt to buy marijuana could have turned into a robbery, a jury that chose to believe that Barber — despite his denial— had been attempting to buy drugs could equally choose to reject his entire account of the events, including the robbery. Thus, the possibility that both an attempted drug buy and (later) a robbery took place did not make inadequate Brown’s proffer of a motive to fabricate which the trial court itself found to be “logically coherent” and founded on the “good-faith basis” of an eyewitness.
In any case, as we have explained, the trial court ultimately accepted the sufficiency of the proffer and did not bar the questioning of Barber on that ground. Rather, the court moved on to what it considered “the next stage of the inquiry,” whether the probative value of the proffered questions about a drug buy exceeded their potential for prejudice in the form of distracting or, worse, inflaming the jury by injection of drug use into the case. Balancing the “weak[ness]” of the proffer against that prejudice, the court prohibited the questioning. The court’s belief that it was authorized to — indeed,- was obliged to — engage in this balancing gives rise to the main doctrinal dispute between the parties on appeal.
Brown contends that once the
Jones! Scull
showing of a genuine belief or well-reasoned suspicion to support the questioning had been made, the trial court could not properly exclude
all
questioning on the subject based upon a weighing of probative versus prejudicial value. Although the court retained discretion as to the amount and, perhaps, the form of the questioning, Brown reasons, it had no authority to disallow “an entire line of cross-examination” related to bias.
Brown I,
This case, we conclude, does not require us to determine the precise nature of the discretion the trial court retains to control (or preclude) bias cross-examination that meets the
Jones/Scull
test. Assuming
arguendo
that the court nonetheless has discretion to preclude questioning about a motive to fabricate supported by a genuine belief on the part of counsel, any such exclusion would have to be undertaken with “the utmost caution and solicitude for the defendant’s Sixth Amendment rights.”
Springer,
An important fact which the trial court relied on in finding Brown’s proffer “weak” was the undisclosed identity of the alleged eyewitness, so that “the [c]ourt [was] not able to test whether the source [itself] had a motive to fabricate” or was “a nonin-volved bystander without a motive to lie.” In a related context, however, we have stated that “[i]n evaluating the reliability of the proffer ... the court must not seek to evaluate the reliability of the witness.”
Newman v. United States,
In keeping with
Brown I, see
The remaining considerations cited by the trial court do not persuade us that exclusion of the bias theory altogether was permissible. The fact, as we stated earlier, that Barber was cross-examined for bias in other respects goes conceptually to whether the error was harmless, not whether error — of the constitutional sort— was committed.
See also Jenkins v. United States,
The trial court conscientiously sought to apply the standards discussed in our opinion remanding the case. We nonetheless conclude that it imposed too great a burden on Brown to proffer evidence supporting cross-examination of the government’s principal witness on the key issue of bias,
see United States v. Abel,
Reversed and remanded for a new trial.
Notes
. Essentially, the trial judge had been of the view that questions as to whether Barber had been trying to purchase drugs at the time of the alleged robbery would be relevant only if there was reason to believe Barber was under the influence of drugs — hence his perceptions were impaired — at the time of the offense.
Brown I,
. In
Brown I,
we noted that "parts of [Barber’s] account of the events ... were arguably quite improbable.”
. As we also determined in
Brown I,
that error could not be held to be harmless on the facts of this case.
. Rather at odds with the trial court’s concern with prejudice from the mention of drugs was its view that the proffer was weak because it ”involve[d] marijuana as opposed to a more dangerous drug,” and that "[a] person trying to buy marijuana has less incen *538 tive to fabricate than one trying to sell marijuana.” As Brown suggests, "If the probative value of the bias evidence is dulled by the purported insignificance of a marijuana buy, so is its prejudicial effect.” In any case, the trial court's own view that an attempted marijuana purchase was too little incentive to fabricate a robbery could not supplant a jury’s, where the effect was to bar all cross-examination on the subject.
