Forensic Evidence in Gang Shooting Investigations

Introduction

Residing in a city with one of the highest rates of violent crime leads to a variety of criminal situations that can be addressed with forensics. A recent event involving a shootout at a local gang site is one such scenario that could provide opportunities to use forensic evidence such as fingerprinting, ballistics, blood analysis, and DNA. In this scenario, a young man was shot to death, but it was not certain who had done the shooting or why. The physical evidence was initially sparse, but there were some clues — including the apparent murder weapon — left behind that could be used by an investigator.

A recent study determined that "in order to link a defendant to a crime, prosecutors have presented expert testimony on a variety of forensic techniques such as DNA analysis, fingerprint comparisons, toolmark comparisons, and bullet lead analysis" (Kaasa, Peterson, Morris, & Thompson, 2006, p. 433). The field of forensic science is constantly showing improvements in evidence-gathering techniques, and in the above scenario, the importance of some of those techniques would become very apparent.

One of the most important pieces of evidence found on the scene was the gun used during the event. It was discovered in an adjacent field and could yield a number of key ingredients in building a case. Those key ingredients include the fact that ballistics tests can be run to determine if the pistol was the actual murder weapon. Additionally, the gun can be dusted for fingerprints as well as examined for any traces of DNA evidence that can be used to identify persons of interest who had handled the weapon.

The Role of Fingerprinting and DNA Evidence

Fingerprinting has been proven as an effective form of gathering evidence and has been used in societies for much longer than many previously believed. One study notes that "fingerprint identification is thus an example of the strategic reorientation of much older techniques by occidental society" (Pollman, 2004, p. 298). Science has shown that individuals possess unique fingerprints, and this fact has been used to validate evidence both for and against defendants for decades.

A newer technology has emerged, however, that can make fingerprinting secondary when DNA evidence is available. Complementing fingerprint analysis with DNA analysis provides a powerful double advantage against the accused. An article in the Journal of Law, Medicine & Ethics espouses the fact that "in a little over twenty years, DNA evidence and the science and technology undergirding it have become highly valued instruments in solving crime, convicting criminals, and exonerating the innocent" (Noble, 2006, p. 149). In this case, fingerprinting and DNA analysis can be used together to establish the identity of the shooter.

Classifying Forensic Evidence

Since it is important to keep track of and ascertain the value of gathered evidence, it makes sense to classify such evidence as it is collected. Evidence can be classified in a variety of ways; one approach is to view it from the perspective of the prosecutor in the case. When described in this manner, evidence falls into three separate categories: favorable evidence, neutral evidence, and harmful evidence. Favorable evidence is helpful to the prosecutor because it assists in establishing motive and supports convictions regarding criminal activities.

Neutral evidence can be regarded as neither helpful nor harmful to the prosecutor's case. Harmful evidence, by contrast, is evidence that weakens the prosecution's position in the eyes of the jury. As the forensic investigator, it is therefore important to bring to light as much helpful evidence as possible.

Conclusion

Deductive reasoning, combined with the weight of forensic evidence, assisted the investigator in establishing that the defendant had shot the victim. When confronted with the overwhelming evidence, the defendant confessed, and the crime was solved. This case illustrates how the disciplined application of multiple forensic techniques — fingerprinting, DNA analysis, ballistics, and blood evidence — can work together to bring about justice even when initial evidence appears limited.

References

Kaasa, S. O., Peterson, T., Morris, E. K., & Thompson, W. C. (2006). Statistical inference and forensic evidence: Evaluating a bullet lead match. Law & Human Behavior, 31, 433–437.

Noble, A. A. (2006). Introduction: DNA fingerprinting and civil liberties. Journal of Law, Medicine & Ethics, 34(2), 149–152.

Pollman, C. (2004). Suspect identities. British Journal of Criminology, 44(2), 297–300.

Schiro, G. (1999). Collection and preservation of blood evidence from crime scenes. Retrieved March 8, 2009, from http://www.crime-scene-investigator.net/blood.html