The strength of the prosecution's case was manipulated, as was the inclusion of extra wiretapping evidence that favored the prosecution of the defense and was ruled admissible or inadmissible by the judge. Whether it favored the prosecution or the defense, inadmissible evidence directly biased subjects' reactions toward the defendant and indirectly biased their behaviors during group discussions. None of these effects varied with the strength of the prosecution's case. The results also showed that the direct effects of inadmissible evidence were at least partially mediated by its indirect effects, suggesting that the process of deliberation can potentially help jurors to control the influence of inadmissible evidence on their decision. Ten footnotes and 17 references are supplied. (Author abstract modified)