The court here denied habeas relief, previously granted by the court below, for a juror misconduct claim based on tampering with an exhibit. Petitioner claimed that his 6th Amendment right to a fair and unbiased jury was violated when the jury was exposed to prejudicial extrinsic information during the trial and during jury deliberation. At trial, an officer witness let slip-out that they did a parole search of petitioner’s residence. Upon objection, the jury was admonished to ignore the comment. But during jury deliberations, the foreperson announced his belief that petitioner had committed a prior felony or felonies based upon lifting the tape that covered a jail booking number on a photo of a witness. Comparing petitioner’s booking number (that was not covered by tape) to that of the booking number of the witness, the foreperson deduced that petitioner’s number was substantially lower, even though they had been arrested the same day, therefore, petitioner must have a prior. However, the jury could not otherwise determine from this how many priors, or the nature of them. A juror’s personal knowledge of specific information concerning a defendant or the crime constitutes impermissible extrinsic evidence. On habeas review, the burden is on petitioner to establish that the extrinsic evidence had “a substantial and injurious effect or influence in determining the jury’s verdict.” The reviewing court applies an objective test in evaluating the potential impact of the evidence on the jury. The appropriate inquiry is whether there was a direct and rational connection between extrinsic material and the prejudicial jury conclusion, and whether the misconduct relates directly to a material aspect of the case. Here the jury never learned the prejudicial details of petitioner’s criminal history, thus the general assertions were not substantial and injurious in the overall context of this trial.