DNA testing as evidence in criminal prosecutions and exonerations

DNA in Trials

The use of DNA in solving crimes has become widely accepted. DNA is now routinely presented in courts as evidence. DNA evidence had helped to identify crime victims and has helped put criminals behind bars. Additionally, DNA is now helping lawyers in defending innocent clients. In many cases, DNA tests have proven the innocence of many prisoners who have been in jail for years. This includes prisoners who would otherwise have been executed.

This paper examines the growing role of DNA testing in the criminal justice system. The first part of this paper discusses the scientific merits of DNA testing, and how these tests contribute significantly to forensic tests and criminal prosecutions. The next part of the paper discusses the precautions that must be taken, to ensure that DNA testing is accurate.

In the conclusion, this paper discusses how DNA testing should be used as a tool for criminal justice. In addition to using the tests to ensure guilt, this paper argues that DNA testing should also be a viable option made available for people who would like to prove their innocence.

DNA Science

Prior to DNA tests, many prosecutors relied on eyewitness testimony to solve crimes. The reliance on witnesses, however, presented was a severe limitation in many prosecutions. Witness testimony could be tainted by bias, prejudice or mistakes.

Months may go by before a trial can commence, which may cloud the memory of many potential witnesses. In addition, many professional killers are able to commit murders and other crimes without any witnesses altogether (Gowen 2002).

In one example, in 2002, DNA evidence led to the conviction of a sex offender for a rape committed in 1982. The same test cleared Bernard Webster, who was convicted based largely on the testimony of the victim and two witnesses. Webster, who had served 20 years, was freed after DNA from the crime ruled him out as a suspect (Gowen 2002).

The use of DNA testing to present biological evidence of a person's guilt or innocence presents a viable alternative to eyewitness testimony. Since DNA or deoxyribonucleic acid is an essential molecule present in every body cell, it becomes more difficult for criminals to erase all evidence of their crime (American Civil Liberties Union 2002).

Further more, since every individual's DNA is unique, DNA is a reliable identifier. Except for identical twins, every person's DNA is unique. Unlike other identifying marks like fingerprints and facial features, DNA cannot be altered. Modern science can thus distinguish between individual DNA samples with great accuracy, making DNA a much-improved version of fingerprinting (ACLU 2002).

Scientific techniques are also improving the reliability and efficiency of DNA testing. Currently, biological evidence must be properly collected and preserved to be accurate. New advances, however, allow forensic scientists are using mitochondrial DNA, which is more plentiful than regular nucleic DNA. This new technique allows investigators to extract DNA evidence from smaller, older and less well-preserved biological evidence fragments (Cohen 1997).

This development will thus help in revisiting older death penalty cases, where the DNA collected was either too small or too degraded for testing.

In summary, because DNA is plentiful and unique to each individual, DNA testing is a much more reliable method of investigating and prosecuting crimes. New scientific techniques will only improve the accuracy of these tests. The use of DNA testing is thus a powerful tool to help prove the innocence of prison inmates who are convicted largely through eyewitness testimony.

What needs to be done

Experts have made suggestions on how to address the problem that are arising due to DNA testing. Additionally, there have been calls to use DNA testing not only to determine guilt but also to prove innocence.

After the Las Vegas crime lab debacle, investigators have added "levels of review" at the crime lab to guard against clerical and transcriptional errors. This is to guard against more paperwork errors. The Las Vegas crime lab now also mandates a second DNA test be done on a sample, before this sample is entered into the computer database. The computerized transcription DNA samples may also help guard against clerical errors (Puit 2002).

The American Board of Criminalistics (ABC) currently offers a certification exam for forensic scientists. Those who successfully pass the exam will be designated as fellows. The exam covers scientific areas that are important to DNA analysis, such as molecular biology and serology. The exam additionally covers law as applied to forensic examinations (Cohen 2003).

This test, however, is not required, and many forensic specialists feel no need to take it.

Additionally, the time- and dollar-intensive nature of the certification process discourages many labs from undergoing accreditation.

As long as there is no legal requirement, many would-be forensic experts do not have the impetus to devote time and resources to the exam and the review process.

DNA testing would also be more reliable and useful if it was more readily available. Towards this, defense experts are advocating free DNA testing should be made available for all people convicted of capital crimes. Opponents, however, argue that DNA testing for prisoners often cite the costs to the taxpayer as well as the potential for abuse. After all, each DNA test can cost up to $5,000 per inmate ("Free DNA Testing for Inmates" 2000).

Corollary to this, DNA testing also involves collecting samples from crime suspects and maintaining a DNA database. The costs to collect DNA sample from suspects and to process and store these samples can run into millions of dollars. The city of Chicago alone estimates the entire process could cost as much as $15 million annually (Possley and Ferkenhoff 2002).

However, cities like San Diego, California are footing the bill for the DNA tests of inmates. As Riverside county assistant district assistant Randy Tagami notes, "Five thousand dollars is not a significant amount of money to determine the guilt or innocence of an individual" (cited in "Free DNA Testing for Inmates" 2000).

Cities which do not have funds for individual DNA testing will benefit from a budget proposal that sets aside $5 million a year to pay for post-conviction DNA testing. This program was enacted after years of lobbying by Democrats like Senator Patrick Leahy, who has campaigned for legislation that will give death row inmates the right to request DNA testing (Eggen 2003).

The government's plan has drawn criticism from both sides. Advocates of DNA testing charge that $5 million is not sufficient to cover DNA testing for all death row inmates nationwide. Opponents, on the other hand, believe that DNA tests could be abused and are a potential waste of taxpayer money (Eggen 2003).

The plan, however, is a step in the right direction and would encourage testing in counties which would otherwise deny prisoners' requests for DNA tests. In addition, a senior justice official maintains that the demand for DNA tests will be limited, since many defendants are actually reluctant to provide DNA samples voluntarily (Eggen 2003).

Both supporters and opponents of capital punishment hail DNA testing as a way to avoid the ultimate nightmare of executing an innocent person. In addition, DNA tests serve as a way to provide poorer innocent defendants with a stronger defense.

Furthermore, the use of DNA testing benefits more than just the potentially innocent inmate. It also serves the larger interests of justice. As Innocence Project director Barry Scheck observes, "Every time you convict an innocent person, a guilty person is out there committing more crimes and has to be stopped" ("Free DNA Testing for Inmates" 2000).

Conclusion

In summary, DNA evidence is a powerful weapon in the fight to catch and convict criminals and to ensure the integrity of the criminal justice process. However, as the more false convictions get exposed, the weaknesses of the DNA testing process are called into question. To ensure the integrity of the DNA process, the accreditation of crime labs should be mandatory. Forensic scientists should also be tested for their scientific and legal knowledge, as it applies to the collection and analysis of DNA evidence. Finally, the authorities should not forget that in addition to determining guilt, DNA also has an opposite capability - determining innocence. To fully harness the capability of this powerful scientific tool, the test should thus be made available for all citizens, especially those in capital cases.