The Contributions of Science to Criminal Justice Investigations, Research Paper Example

Introduction

Science has contributed to criminal investigations for nearly as long as modern professional police forces have been in existence. One of the first such technologies was fingerprint analysis, which led to “screening” of potential suspects for crimes in the 1940s. (McCartney, 2006, 179). Fingerprints can now be detected and lifted from many more materiasl than before. According to Kirsch, these include

materials as varied as leather and cloth, which were previously considered unprintable, by using cynaocrylate fingerprint systems. In addition, automated fingerprint identification systems and systems that use lasers to lift prints aid investigators (Kirsch, 2006, 34).

More recently, the genetic compound, deoxyribonucleic acid (DNA) has been used in mass screenings. The first known mass screening took place in the United Kingdom in January 1987 when police took DNA samples from all males between 16 and 34 years in three villages to identify a serial rapist. The samples did not identify the rapist, but they did confirm that a single rapist was involved and that the man who confessed to the second rape was in fact not the person who committed that crime. (McCartney, 2006, 179).

DNA is present in all cells of the body. Nuclear DNA is the common concept of genetic inheritance. It derives from both the father and the mother. However, nuclear DNA is rare and fragile, making it hard to obtain quality samples in some conditions. DNA is also present in the cells’ mitochondria, small organelles outside the cell nucleus. Mitochondrial DNA, often denoted as mtDNA, is inherited only from the person’s mother, so it does not reflect paternal inheritance. Mitochondrial DNA is much more plentiful in cells than nuclear DNA, and thus it is obtainable from older or more damaged samples than nuclear DNA. (NLECTC, 2010).

With the advent of many television and film programs in which DNA analysis is the “magic bullet” that instantly solves crimes, there is often a belief among the public that DNA analysis is a foolproof method of finding criminals.

This paper addresses the effectiveness of DNA in criminal investigations, its usefulness in reopening and solving “cold cases,” and the limitations that arise in DNA analysis.

Innovations in DNA

One of the earliest innovations in DNA analysis for criminal investigators was the development of the polymerase chain reaction (PCR) in which very small samples of DNA can be “amplified” into larger samples that are of testable size (Kirsch, 2006, 35).This allowed collection of DNA in more cases.

A second innovation was development of the short tandem repeat (STR), which analyzes specific portions of nuclear DNA to determine a match. This primarily allows determination of mis-matches if there is any kind of variation between, say, a suspect’s DNA and that collected at the scene of a crime. (Ibid.)

Yet a third development was the use of mtDNA rather than nuclear DNA. This allows collecting evidence from such sources as hair samples and bones, which generally don’t allow nuclear DNA analysis. For example, nuclear DNA is only available in the follicles of hairs, but mtDNA can be obtained from the hair shaft. (Kirsch, 2006; NLECTC, 2010). As the NLECTC reports, “For hair analysis, mtDNA is the gold standard.”

One caveat arises with mtDNA because it only derives from the mother and not the father. However, it can be used to identify human remains if comparison mtDNA is available for comparison from someone else in the maternal line. (Kirsch, 2006).

Recent innovations in mtDNA analysis include dramatic increases in the speed with which mtDNA can be screened. For example, the National Law Enforcement and Corrections Technology Center (NLECTC) reported in 2010 that a new development in mtDNA analysis permits initial screenings could be done in as little as seven minutes. This allows quick determination of which samples require further analysis with more detailed methods. Furthermore, additional developments allow samples that contain mtDNA from two individuals to be sorted and identified with 100% accuracy. While this technique is not suitable for mixtures of three or more people, and it requires sophisticated software to complete the analysis, the prospect for future developments is rosy (NLECTC, 2010).

Uses of DNA Testing in Criminal Investigations

One example of how DNA evidence can assist in the identification and conviction of a criminal lies in the 2004 vicious murder of the 92-year-old Agnes Schmidt in Highland Township, a suburb northwest of Detroit, Michigan. This vulnerable old woman was assaulted in her home in one of the most violent attacks the investigating detectives had ever seen. Safarik and Wurtz describe her body, when discovered the morning after her murder:

Agnes Schmidt lay crosswise on her bed, nude except for her socks. Her clothing was strewn about the floor of her bedroom, inside out. She had suffered 23 stab wounds to her neck, chest, and abdomen including four to her vagina. The offender left the knife he had taken from Agnes’s own kitchen embedded in her abdomen. (Safarik and Wurtz, 2006).

In the investigation that followed, the detectives made use of the FBI’s Violent Criminal Apprehension Program (VICAP) and the Behavioral Analysis Unit for a profile of Agnes’s killer. One name, David Ream, showed up near the top of their list of suspects. After obtaining DNA from Ream, forensic analysis of the sample matched a pubic hair found on the victim’s body. The result, combined with other solid police work and evidence collection, resulted in a conviction. David Ream was sentenced to life imprisonment on January 31, 2006. As Safarik and Wurtz concluded, “The successful closure of the case was the direct result of the well-coordinated investigative efforts and communication between detectives, scientists, and violent crime experts at the FBI.” (Ibid.)

In 2000, Australia initiated a “DNA Expansion Programme” designed to increase the national database of known criminals, estimated at that time to be approximately three million individuals. Within five years, the database had achieved the estimated total of 2.9 million people. McCartney reports that “Since this first use of a DNA screen, the police have increasingly resorted to screens to solve serious crimes, with there being 292 screens utilized across England and Wales between April 1995 and January 2005.” (McCartney, 2006, 179).

Those databases appear to be helpful in solving crimes. McCartney reports that “The clear-up rates for crimes where DNA evidence is available are significantly higher than those crime scenes with no DNA evidence recovered, with the overall detection rate of 23.5 per cent rising to 38 per cent (although the government claim a rise to 43 per cent)30 where DNA is successfully recovered.” (Ibid., 182).  Yet, according to Connors, et al., such mass DNA screenings are unlikely to become prevalent in the U.S. because of constitutional protections against unwarranted search and seizure. (Connors, et al., 2003).

One of the most useful areas of DNA testing in criminal investigations has been in re-opening cold cases. Kirsh reports that often DNA evidence can be obtained from evidence preserved from the original investigation, even when many years have passed since the crime. With the technology improving all the time, the preservation of evidence in unsolved crimes becomes critical to future forensic investigations. (Kirsch, 2006). One example of how cold cases can be closed many years after the crime using improved DNA analysis techniques is shown in the murder of Celia Douty, who was found bludgeoned  to death on Brampton Island, on the Great Barrier Reef in Australia. At the time of her death in 1983, DNA analysis was not sufficiently advanced  to use in the investigation. However, in 2001, on the basis of a semen stain on the towel covering her body, Wayne Butler was tried and convicted. The DNA analysis matched to his DNA sample with odds of 1 in 23×10¹⁵.  Butler was sent to prison for life as a result of his conviction. (Briody, 2004, 233).

The Use of DNA Evidence at Trial

Current U.S. trial standards for the admissibility of scientific forensic evidence are based on a standard from a case from the 1930s, Frye v. United States. Kennedy summarizes those standards as:

• Whether the theories or techniques on which the testimony are based on a testable hypothesis;
• Whether the theory or technique has been subject to a peer review;
• Whether there is a known or potential rate of error associated with the method;
• Whether there are standards controlling the method; and
• Whether the method is generally accepted in the relevant scientific community (Kennedy & Merrill, 2003, 33).

Perhaps in part due to the prevalent television shows and  movies illustrating the validity of DNA evidence, studies show that juries tend to take DNA very seriously when it is part of the prosecution’s case.  According to Connors, et al. there is greater and greater demand for the prosecution to get DNA evidence in the pre-trial phase of investigation to help exclude suspects as early as possible. Lundregan, et al. believes this will save prosecutors  money in the long run because investigations will quickly be directed toward the real perpetrator(s) of the crime.

So how do jurors perceive DNA evidence at trial? Briody conducted a 2004 analysis of the effects of various types of evidence in homicide cases in Queensland, Australia.  Cases with DNA evidence were fourteen times as likely to go to trial as cases without DNA evidence.  And, if taken to trial, cases with DNA evidence were 23 times more likely to result in a conviction than cases where DNA evidence was not available. (Similarly, fingerprint evidence, another scientific forensic test, was also strongly linked to convictions.) (Briody, 2004, 242).  It is clear that juries take scientific evidence such as DNA evidence very seriously indeed. Based on these results, such evidence is strongly trusted by jurors.

Issues With DNA Evidence

DNA profiling screenings have repercussions for civil liberties. For example, McCartney reports that:

In the recent ‘Operation Minstead’, 1,000 black men in South London were ‘profiled’ in the hunt for a serial rapist; those men were then requested to volunteer for DNA tests. Of those, 125 initially refused, leading to ‘intimidatory’ letters from the police, urging re-consideration, and five were arrested, their DNA taken post-arrest and added to the NDNAD. Such actions have raised questions of legality, with arrests only lawful with ‘reasonable suspicion’ of an individual having committed a criminal act. If the police are to arrest on non-compliance with a DNA request, then that casts non-compliance as a crime—a step that worries civil libertarians (McCartney, 2006, 180).

The existence and retention of DNA databases has been challenged in courts in Europe as violations of the right to privacy.  According to Williams and Johnson, the right of police to take DNA samples from suspects when taken into custody is not generally argued, even if there is no usable DNA evidence from the crime they are suspected of.  What is in contention in Great Britain is whether the police have the right to retain such samples for those who are not convicted of the crime. The question is whether such retention is a violation of European citizens’ right to privacy. The trend in England seems to be towards allowing the police to retain such samples in a database for anyone suspected, if not convicted, of a crime. This remains an ongoing issue of contention with DNA databases. (Williams & Johnson, 2006, 238-239).

There have also been cases where prosecutorial or police misconduct have resulted in invalid convictions. This behavior, however, is not limited solely to forensic evidence. As Kennedy and Merrill point out, “Recognizing that no science consistently produce certain results, courts are also questioning the error rates associated with forensic identification techniques.” (Kennedy and Merrill, 2003, 34).

Conclusions

The use of forensic science, particularly that of DNA testing, has proven its value in the investigation of crimes all over the world. DNA analysis techniques are continuously improving and allowing extraction of DNA evidence using smaller and smaller samples, and with greater speed. This technology has proven useful in closing cold cases to a strong degree. Furthermore, the evidence is effective in court, with cases that have DNA evidence garnering convictions at a substantially higher rate than cases without DNA evidence.

With all that said, there are still issues with DNA evidence in the U.S., including constitutional rights preventing self-incrimination. While screening and a national database of DNA of suspected criminals has been established in Great Britain, it’s not clear that they will ever be acceptable in the U.S.

Despite these concerns, there is no doubt that forensic science is a proven valuable aid to criminal investigations.

References

Briody, M. (2004). The effects of DNA evidence on homicide cases in court. Australian and New Zealand Journal of Criminology. 37 (2). Retrieved from http://anj.sagepub.com.ezproxy2.apus.edu/content/37/2/231.full.pdf+html.

Connors, E., Lundregan, T., Miller, N., & McEwen, T. (1996). Convicted by juries, exonerated by science: case studies in the use of DNA evidence to establish innocence after trial. Retrieved from http://www.ncjrs.gov/pdffiles/dnaevid.pdf.

Kennedy, D. and Merrill, R. A. (Fall 2003). Assessing forensic science. Issues in Science and Technology, 33-34.

Kirsch, L. (2006). Heating up cold cases. Forensic Examiner, 15(2), 34-35. Retrieved from http://proquest.umi.com.ezproxy1.apus.edu.

McCartney, C. (2006). The DNA expansion program and criminal investigation. The British Journal of Criminology. 46 2. Retrieved from http://bjc.oxfordjournals.org/content/46/2/175.full.

Mondor, C. (2010). Genetic justice: DNA data banks, criminal investigation, and civil liberties. The Booklist. 107 (5). Retrieved from http://proquest.umi.com.ezproxy2.apus.edu/pqdweb?index=5&did=2184146211&SrchMode=1&sid=2&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1295959745&clientId=62546.

NLECTC (2010). Innovation in DNA analysis. TechBeat. Retrieved from http://www.justnet.org/TechBeat%20Files/Innovation%20in%20DNA%20Analysis.pdf.

Safarik, M.E. and Wurtz, D.G. (Fall 2006). Investigation, Science, and Research Partner to Solve Elderly Woman’s Shocking Homicide. Journal of Forensic Nursing, 2, 3, 127-129.

Williams, R. and Johnson, P. (Fall 2005). Inclusiveness, effectiveness and intrusiveness: Issues in the developing uses of DNA profiling in support of criminal investigations. Journal of Law, Medicine & Ethics, 33, 3, 545-558.