Unimpressed With Probative Use Of Polygraph Evidence

In a terrorist conspiracy case involving a plan to attack Chicago's Sears Tower, trial judge barred defendant from questioning government informer about a polygraph test the informer had failed over a decade previous to defendant's trial on terrorism charges, in United States v. Augustin, _ F.3d _ (11th Cir. Nov. 1, 2011) (No. 09-15985) (per curiam)

As a general matter, "the results from a polygraph test are not admissible at trial, unless the results are offered not for a non-hearsay purpose." On earlier example of this principle was previously described by the Federal Evidence Blog in which a defendant "opened the door to evidence concerning his polygraph examination." See Opening The Door To Polygraph Evidence. But some doors open wider than others. The Eleventh Circuit recently considered a case in which the door did not open much at all, so that the defendant could not use a witness's polygraph result as a means of impeaching the witness.

As previously described in a blog essay focusing on Confrontation Clause issues, see Contextual Use Of Recorded Conversation Did Not Violate Confrontation Clause the defendants in the case were prosecuted for conspiring to provide material support to a Foreign Terrorist Organization, specifically “Al Qaeda.” At trial, a substantial portion of the evidence included testimony by an "FBI informant, Ellie Assaad (“Assaad”), who was posing as [cooperating witness] Abbas’s foreign terrorist connection." Augustin, _ F.3d at __

In order to impeach the informant's testimony, the defendant sought to question the informant about a polygraph test the informant "failed in 1997." Defendant's theory for the admission of this evidence had its foundation in "Federal Rule of Evidence 608(b) [which] commits to 'the discretion of the [district] court' the determination as to whether specific instances of conduct," could be admitted as "probative of truthfulness or untruthfulness” of the witness. The defendant proposed cross-examining the informant about the failed polygraph test. Augustin, _ F.3d at __

The circuit evidently agreed with the trial court that the polygraph evidence was not sufficiently probative to over-come the reasons for excluding it. The evidence was not only stale, but it was also of questionable value. As noted the circuit

The polygraph that is at issue in this case was administered more than a decade before the third trial took place. Beyond that, we have acknowledged that there may be substantial limitations to the reliability of polygraphs. Bearing this in mind, we cannot say that the district court abused its discretion in determining that the polygraph was not probative of truthfulness and that therefore, it could not be the subject of cross-examination."
Augustin, _ F.3d at __ (citing United States v. Henderson, 409 F.3d 1293, 1303 (11th Cir. 2005)).

While undoubtedly not much more than dicta, the Augustin case demonstrates the simple barriers that can block the use of polygraph evidence, even if it remotely might be considered an issue.

Federal Rules of Evidence