Wrongful convictions (Forensic Science)
Forensic science has made significant contributions to attempts to rectify the problem of wrongful convictions in the United States. Modern understanding of DNA (deoxyribonucleic acid) and advances in DNA analysis technology, in particular, can be credited with aiding the courts in exonerating hundreds of innocent individuals who had been wrongly convicted. Ironically, these exonerations have often involved the use of one form of forensic evidence (particularly DNA evidence) to discredit earlier findings based on other forms of forensic evidence (such as blood typing, fingerprints, ballistics, bite marks, foot prints, or hair comparisons). In cases of exoneration, what typically occurs is that evidence preserved from the incarcerated person’s original trial is reanalyzed using modern DNA technology, and this new analysis proves conclusively that the individual is not linked to the crime.
Researchers have studied the case files of many persons proved to have been wrongfully convicted to understand the ways in which the criminal justice system can malfunction. This work has provided a wealth of information on the factors associated with wrongful conviction.
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The Double-Edged Sword (Forensic Science)
For the criminal justice system, forensic science is a double-edged sword. On one hand, when properly used, it can be a powerful tool that serves justice; forensic scientists help police, prosecutors, defense attorneys, judges, and juries do what they are supposed to do—that is, exonerate the innocent and convict the guilty. On the other hand, when the forensic evidence presented in a courtroom is faulty, it can mislead the judge or jury and result in the conviction of an innocent person. The stakes are high when forensic science enters the courtroom, as it is often the testimony of forensic scientists that ultimately sways the judge or jury in the determination of guilt or innocence.
Although some criminal cases are tried without the benefit of forensic evidence, possibly with only eyewitness testimony, the vast majority of criminal cases rely on the expert testimony of forensic scientists, who present to the court their opinions regarding what the physical evidence means in terms of the defendant and the crime. Because evidence involving genetic materials (such as blood, skin, and semen) is available in less than 20 percent of all cases, the most powerful tool available to forensic science—DNA analysis—is not used in more than 80 percent of criminal cases. In cases where genetic material is not available for analysis, scientists are usually called upon to analyze fingerprints, handwriting, ballistics, tool...
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Misrepresentation of Scientific Findings (Forensic Science)
Faulty forensic science can contribute to a wrongful conviction in two ways: through unintentional or intentional misrepresentation of the scientific findings. Forensic scientists can unintentionally present faulty findings in the courtroom for a variety of reasons. Research into cases of wrongful conviction has found that the work of forensic technicians in some police crime laboratories is plagued by uneven training and questionable objectivity. Poorly trained or lazy technicians can conduct forensic tests that yield inaccurate results.
Forensic scientists can also commit unintentional errors in the form of inadvertent mislabeling or switching of samples, mistaken recording of data, inaccurate transcription of results, and loss of evidence. Sometimes the results of scientific tests are themselves accurate but unintentional misinterpretation of the data harms the wrongfully accused. In sum, faulty scientific testimony resulting from either erroneous lab tests or erroneous conclusions based on valid lab tests can lead to wrongful convictions.
Sometimes forensic experts intentionally misrepresent the scientific findings in court. In a study of sixty-two wrongful convictions, the Innocence Project (a nonprofit organization founded at the Benjamin N. Cardozo School of Law to assist prisoners who could be proven innocent through DNA testing) found that so-called rigged lab tests often contributed...
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Indirect Effects of Forensic Error (Forensic Science)
It has been recognized for years that faulty forensic science can contribute directly to wrongful conviction, but for a long time little attention was paid to the degree to which faulty forensic science can indirectly lead to wrongful conviction by contaminating seemingly independent nonscientific evidence. For example, eyewitnesses who have misidentified a criminal suspect may become increasingly confident in their identification once they discover that forensic scientific tests (whether erroneous or not) have verified their statements. Given that “witness confidence” has been demonstrated to have a strong influence on jurors’ perceptions that identification testimony is correct, erroneous conclusions by forensic scientists in such cases are particularly dangerous. In sum, faulty forensic findings may influence and encourage other participants in a trial (witnesses, police officers, prosecutors) to rely more strongly on their own erroneous conclusions.
The damage done by faulty forensic science not only affects the original trials of wrongfully suspected individuals but also continues to plague them when their cases are being appealed. Even when it is discovered that erroneous scientific testimony was offered at trial, the prosecutor will typically say that the testimony amounts to “harmless error” and that the conviction would have occurred even if the faulty evidence had not been presented. The...
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Reducing Forensic Error (Forensic Science)
Given that human beings will always make mistakes, the phenomenon of wrongful conviction is unlikely ever to be eliminated totally. It is, however, possible to reduce the amount of faulty forensic science presented in courtrooms and thereby reduce the likelihood of wrongful convictions. Forensic science is subject to the influence of human error at every step, beginning with the collection of evidence and on through the storing, testing, and interpretation of that evidence. Forensic scientists must diligently apply their training and ensure that the testimony they offer in court is as scrupulously accurate as humanly possible. Forensic experts who intentionally misrepresent their data should be prosecuted to the fullest extent of the law.
Government standards regarding the training of forensics laboratory personnel and the preservation and handling of evidence have been strengthened in the United States over the years, and aggressive enforcement of these standards should reduce error. Also, lawyers have the responsibility and obligation to their clients to challenge flawed scientific testimony; law schools and continuing education seminars should promote training for attorneys that will help them better recognize and challenge specious forensic testimony.
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Further Reading (Forensic Science)
Connors, Edward, Thomas Lundregan, Neal Miller, and Tom McEwan. Convicted by Juries, Exonerated by Science: Case Studies in the Use of DNA Evidence to Establish Innocence After Trial. Washington, D.C.: National Institute of Justice, 1996. Government research report discusses a study initiated to identify and review cases in which convicted persons were released from prison as a result of posttrial DNA testing of evidence.
Gross, Samuel R., et al. “Exonerations in the United States, 1989 through 2003.” Journal of Criminal Law and Criminology 95, no. 2 (2005): 523-560. Analyzes 340 individual exonerations during the period covered. Notes that the data suggest that the total number of miscarriages of justice in the United States in the preceding fifteen years must run to the thousands, perhaps tens of thousands, in felony cases alone.
Huff, C. Ronald, Arye Rattner, and Edward Sagarin. Convicted but Innocent: Wrongful Conviction and Public Policy. Thousand Oaks, Calif.: Sage, 1996. Examines the full range of cases in the United States in which innocent people have been falsely accused, convicted, and incarcerated and describes the variety of missteps in the criminal justice system that can lead to unjust imprisonment.
Radelet, Michael L., Hugo Adam Bedau, and Constance E. Putnam. In Spite of Innocence: Erroneous Convictions in Capital Cases. Boston: Northeastern University...
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