Detective Mark Fuhrman's dishonest testimony in the O.J. Simpson trial underscores the serious problem of police perjury in the U.S. legal system, a University of Illinois law professor says. Although no one knows exactly how widespread police perjury is, many experienced trial lawyers have said they believe police officers frequently lie on the stand, professor Donald Dripps said.
Preliminary studies appear to back up that belief.
The temptation to lie may be greatest during evidence-suppression hearings, which are heard by a judge rather than by a jury, he said. Crucial evidence can be suppressed if a judge rules that an officer violated the Constitution by entering a residence without a search warrant or failing to obtain consent to search the trunk of a car, for example. Judges are far more likely to credit an officer's testimony, even if they're skeptical of it, over the testimony of a defendant caught with a suitcase full of drugs. Lie detectors would be used to help establish witness credibility when a judge's ruling hinged on the conflicting testimony of a defendant and a police officer, he said. Although neither party would be forced to take a polygraph exam, both would have the opportunity to enhance the credibility of their testimony by taking a polygraph test.