Misconduct in the prosecution of severe crimes: Theory and experimental test

Prosecutorial misconduct involves the intentional use of illegal or improper methods for attaining convictions against defendants in criminal trials. Previous research documented extensive errors in the prosecution of severe crimes. A theory formulated to explain this phenomenon proposes that in serious cases, increased pressure to convict encourages misconduct; further, serious cases increase perceptions of the suspect's guilt, which facilitate justification of the misconduct. A controlled laboratory experiment allows tests of theoretically derived predictions while controlling for extraneous factors common in naturally occurring settings. University undergraduate participants were assigned randomly to prosecute a contrived case of murder or assault; otherwise the two cases were identical. Results showed that participants improperly withheld exculpatory evidence from the defense more often in the murder case than in the assault case. Further, participants prosecuting the murder case expressed a stronger belief in the defendant's guilt than did participants in the assault case. Implications for future research in naturally occurring settings are discussed.