DNA Evidence and Its Role in Criminal Investigations

Introduction

The use of DNA evidence in the investigation of crimes in America dates back to 1987. Before this period, many cases remained unsolved due to a lack of sufficient evidence. Jobling and Gill (739) report that the late 1980s were characterized by problems related to admissibility. Thus, there was a high level of scrutiny concerning the DNA evidence within the judicial realm. However, these challenges were solved in the early 1990s following the advancement in the Polymerase Chain Reaction (PCR) techniques. Currently, DNA profiling is widely acceptable in solving crimes related to robbery, rape, and murder. The technology has also enhanced solutions of cold cases such as the ‘Green River’ killings. The current research aims to assess the evolution of DNA evidence and establish its effect in investigating crimes.

Evolution of DNA evidence

The application of DNA technologies in the 1980s and 1990s was greatly criticized since the methods were new and few studies had been focused on their validity and reliability. Despite the scrutiny, Cormier, Calandro, and Reeder (1) note that the technique was critical in the exoneration of suspects accused of various offenses. The technique was originally developed in an effort to establish the results of paternity tests in civil cases. Particularly, it was employed in cases where children or parents wanted to determine whether they were genetically related to one another. It was not until 1985 that the judicial system allowed the use of DNA technology in criminal investigations. According to Jobling and Gill (740), the technique was first used in forensic investigations in England to vindicate a 17-year-old rapist. Alec Jeffreys, a molecular biologist, was the first individual to apply the technique in forensic investigations. Based on the results of the test, the 17-year-old boy was found guilty of the sexual assault crimes. In 1987, the method was used in the conviction of Tommy Lee in a rape case in America (Cormier, et al., 1). The Circuit Court in Orange County Florida made a unanimous decision to accept the evidence-based on DNA testing despite the outcry from other judicial actors. During these cases, there were no arguments relating to the admissibility of the test. As the technique became widely used in various cases, many judicial players started questioning its admissibility.

In reference to Cormier et al. (2), defense teams questioned the consistency of the technique throughout the early 1990s. During this period, forensic scientists applied two major techniques in determining the admissibility of the method. First, the Frye standard was popular in the United States courts. The standard stipulated that the DNA evidence would only be permissible if it was acceptable within the judicial system. However, using the Frye standard inadmissibility cases proved to be difficult as most of the defense teams failed to accept the technique (Jobling and Gill 741). Second, the Daubert standard was developed in 1993 to deal with the issues affecting the previous standard (Cormier, et al., 2). The United States Supreme Court established the standard and it was a modification of the Frye Standard. Notably, the Supreme Court argued that the evidence also had to be valid and reliable. Regarding validity, the DNA results were required to tell the truth about the case being investigated. In order to be justified, the test had to generate identical results in the course of all evaluations held. The Daubert Standard is more acceptable in forensic testing today. Despite the advancements in the overall test recognition, Jobling and Gill (744-746) outline several challenges that affected the acceptance of the DNA evidence. The major challenge was to determine the best procedure to promote the reliability of the evidence. In the case of the people of New York versus Castro, reliability challenges were evident. Specifically, the pre-trial court questioned the laboratory reliability techniques used that were used to test the blood samples on the offender’s watch. The court also found out that the forensic laboratory had failed to prove without a doubt that the blood belonged to Castro.

Cormier et al. (2) acknowledge that the laboratory admissibility testing procedures are complex and exhaustive and this represents a challenge to forensic investigations. In the early 1990s, the Supreme Court also ruled that the reports on the laboratory procedures and results must be presented to the courts in an effort to confirm their validity and reliability. Moreover, forensic scientists are required to present statistical calculations in support of the results. Jobling and Gill (743-744) indicate that the evolution of the DNA evidence between the 1980s and the 1990s was characterized by admissibility challenges. However, the technique underwent various advancements in the late 1990s and the 2000s. Specifically, forensic scientists developed more specific Polymerase Chain Reactions (PCR) that employed short tandem repeats in sequencing. In 2001, many courts in the United States continued to argue that the technique was valid and insisted that it should no longer be scrutinized (Cormier, et al., 3). Thus, the admissibility of the forensic technique was no longer an issue. Currently, the application of DNA technologies in forensic science is greatly supported within the judicial realm. Moreover, many legal reviews have been undertaken to prove the validity and accuracy of the technique.

Effect of the DNA evidence on criminal investigations

Wilson, McClure, and Weisburd (458-461) note that DNA evidence improved the efficiency of the judiciary in making decisions regarding criminal investigations. Since every individual has unique genes, it is possible to apply the technology in law enforcement initiatives. The technology enables forensic scientists to rule out or prove that a certain individual was responsible for committing a crime. Jobling and Gill (741-742) indicate that DNA profiling procedures are highly accurate and have been effective in solving murder cases in the past. Moreover, the technique is used to exonerate innocent victims and hence ensure that justice is upheld in criminal cases. Wilson et al. (459-460) note that the DNA evidence has been effective in solving various cases in the United States and hence safeguarding the safety of the citizens. An example involves the 22 cases of sexual assault reported in New York City in 1999. DNA evidence provided support that the same person committed the sexual assaults and this led to his arrest. As a result, the criminal was no longer a threat to the security of the citizens. DNA evidence is also critical in solving ‘cold cases’ (Jobling and Gill 743-744). The ‘Green River’ killings case, for example, was solved in 2001, after many vain efforts to draw consistent proofs. Specifically, forensic scientists were able to determine that the samples collected from the various crime scenes belonged to the same person. Thus, DNA evidence promotes closure among the victims and their families and enables them to move on with life. In addition, cold cases cost the United States millions of dollars and hence DNA evidence reduces such losses. Cormier et al. (3) outline two major ways that DNA evidence has been used in criminal investigations. First, it enables the comparison of the offender’s DNA with the evidence at the crime scene. This enables the investigators to narrow down the number of people suspected of committing the crime. Secondly, DNA evidence is important in comparing the suspected DNA with online DNA databases. The United States crime investigation teams employ the Combined DNA System (CORDIS) database in identifying suspects. The database has also been critical in comparing evidence from different crime scenes.

Conclusion

The use of DNA evidence in the investigation of crimes has been in existence since the mid-1980 (Cormier, Calandro, and Reeder 1-2). The technique was first employed in Britain to solve a sexual assault case. It was not until 1987 that the method was used in the conviction of Tommy Lee in a sexual assault case in America. Despite the success of the DNA evidence in the case, there were concerns regarding its admissibility in the court of law. It faced countless objections from the majority of lawyers. The Frye and Daubert standards were introduced by the courts to ensure that the evidence was scientifically based and promote the validity and reliability of the technique. DNA evidence became more acceptable from the late 1990s when more advanced PCR and sequencing procedures were introduced. Generally, DNA evidence has played a role in the exoneration of suspects and conviction of offenders, It has also been critical in solving cold cases.

Works Cited

Cormier, Karen, Lisa Calandro and Dennis Reeder. “Evolution of the DNA evidence for crime solving: A judicial and legislative history.” Forensic 2.4 (2005): 1-3. Print.

Jobling, Mark A and Peter Gill. “Encoded evidence: DNA in forensic analysis.” Nature Reviews 5.3 (2004): 739-751. Print.

Wilson, David B, David McClure and David Weisburd. “Does forensic DNA help to solve crime? The benefit of sophisticated answers to naive questions.” Journal of Contemporary Criminal Justice 26.11 (2010): 458-469. Print.