Research data were obtained from a random sample of the registered voter list in St. Louis County, Mo. A total of 305 home interviews obtained demographic characteristics, personal history information, and attitudes of voters, to operationalize the variables under consideration. In addition, a hypothetical case was presented to each respondent. The vignette was based on a transcript of an actual jury trial involving a young, black male charged with murder under the State's felony-murder rule. The transcript showed that the prosecutor's case was based almost entirely on police testimony pertaining to the identification of a suspect, the recovery of incriminating physical evidence, and initial statements made by the accused. The defense in the case suggested that the police, saddened by the death of a fellow officer, were falsifying information in their eagerness to punish the accused. The defense attempted to highlight inconsistencies in police testimony and interpret the existence of incriminating evidence as due to a police conspiracy. Case-relevant attitudes were examined as attitudes toward the police and punishment. Data suggest that the strength of the exidence is influenced by case-relevant juror attitudes. Attitudes toward those issues constituting the basis for the case and toward those social groups which testify during the trial influence a juror's perception of the strength of the evidence presented. These attitudes, however, contribute to the juror's verdict only indirectly. Verdict is directly affected by the perceived strength of evidence, which is in turn related to juror's case-relevant attitudes. Although these results are tentative because of research limitations, they suggest that strength of exidence variables must be included in systmatic jury selection procedures. Tabular and graphic data, footnotes, and 32 references are provided.