Forensic Trace Evidence

Forensic trace evidence

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Fabio Duarte Colombo

Student ID: 18279940

Forensic Trace Evidence

The study of the crime evidence plays a crucial part in investigations of crimes. Countries that have professionally trained crime investigators and advanced laboratories for crime evidence study tend to have a more effective criminal justice system, compared to those countries have no trained crime investigators and laboratories. For example, Ladapo (2011) explain that the inefficiencies in the Nigeria criminal of justice are related to the poor and ineffective criminal investigations. Otherwise, an effective criminal justice system may have a deterrent effect on criminals. Criminals may estimate the probability of being caught when judging to commit a crime or not. Also, as the traces evidence investigations find answers, it makes pressure to the murderer confess the crime. According to “Understanding the progression of serious cases” (2016) report, there are 21% of crimes have no witnesses. For cases without witnesses, crime investigations may highly depend on the scientific evidence collected by crime investigators in crime scenes. Advanced analytical instrumentation has been widely used to assist the investigation of minuscule materials such as fingerprints and body fluids in the crime scene. For example, capillary electrophoresis, Raman spectroscopy, and infrared spectroscopy (Houck & Siegel, 2015). Numerous case studies have demonstrated how crime technologies help crime investigators and police to solve cases via examining the physical evidence from crime scenes. The purpose of this essay is to argue that physical evidence let in a crime scene can be used to assist the investigation of crimes via evaluating relevant case studies such as Spokane Cereal murder. In particular, it will analyse how Fibres, DNA, fire debris, vomit, body fluids, and human hair can be considered as evidence to examine crime scenes.

In cases where the victim through up before to die, the vomit is an effective and useful trace evidence. Because the vomit composition is exclusive, being composed of partially digested ingredients of the last meals and gastric enzymes (Houck & Siegel, 2015). In addition, the smell is strong, easily finding if present in any possible item that had contact with it. So, any fluid present in the victim’s clothes and belongs can be compared using a microscopy Houck & Siegel (2015). In the case of Cereal killer in Spokane, that happened in 1999, the victim’s vomit was an essential trace evidence to discover who was his murderer. Kevin, the 11 years old son of James Cochran, was missing after their house be found on fire (Lecture Notes 2, 2016). Two days after, the Kevin’s body was found along the road with a large amount of vomit, with the shoes on the wrong feet (Lecture Notes 2, 2016). According to (Lecture Notes 2, 2016) the autopsy determined that he died by strangulation. The investigators found several droplets in the Cochran’s pick-up truck that look and smell like vomit. Kevin’s sisters stated that the last thing that she saw Kevin eating was a breakfast cereal, then, this cereal was recovered by the police (Lecture Notes 2, 2016). According to (Lecture Notes 2, 2016), examining the samples using microscopy was possible to visualise a similar structure in the Kevin’s vomits and the droplets in Cochran’s car. Both have a structure in oat flour, and cell coating the oat bran, that are ingredients present in the cereal that kelvin had eaten (Lecture Notes 2, 2016). In addition, vomit with the same composition was found in a garbage can not far from the place where the body was found (Lecture Notes 2, 2016). These ingredients were expected to be found in his vomit after his partial digestion. These evidences were enough to incriminate his father and to put him in jail. To conclude, microscopy examination and vomit composition were essential to creating an incontestable narrative about the crime.

The soil is made up a large range of materials that allow the soil scientists distinguish soils from different places and to use as contact evidence. The soil is a mixture of a variety of sized mineral, oxides, organic matter and microorganism (Sugita & Marumo, 1996). In addition, there are the anthropogenic soils, which are soils with high human influence, with cemented or paint materials, for example, suggesting that it is from an urban area (Jamieson & Moenssens, 2009). In addition, in the cases of the victim is buried to hide the body, the soil PH, temperature and composition can be used to estimate how long ago the victim died ("Soil Characteristics that Impact Clandestine Graves", 2016). Fitzpatrick (2013) explain that soil is a highly distinguishable material, can be almost invisible in the crime scene, it is easily characterized and has a high likelihood to transfer. Furthermore, in order to facilitate investigations, some countries create a soil mapping, making possible to have a notion about where a soil found in a crime scene is from just checking a database (Fitzpatrick, 2013). Several key items in a crime scene can carry the soil, such as the shoes, the car’s wheels, a spade used to bury the victim. Woods et al. (2014) demonstrated that the Energy-dispersive X-ray spectroscopy is one of the most precise technique to discriminate soils. In the cereal murder case, crushed rock, soil, grass and pine needles was found in front offender and tow hook of Cochran’s pick-up truck (Lecture Notes 2, 2016). This soil mixed with other materials was compared with the soil taken along the Chatsburg road, where the victim’s body was found. Using polarized light microscopy was possible to identify the existence of phytoliths in both soils and the soil composition was similar, indicating that Cochran drove until the crime scene (Lecture Notes 2, 2016). Another example of how useful is the soil analyses is the case of two missing women and their car in Adelaide described in details by Fitzpatrick & Raven (2012). The police found their car 200km from their house with a shovel inside it. The forensic soil scientists analysed soil in the shovel and suggested that the soil is from the local industrial soil gravel quarries. As a result, the police found the burial site. Despite, the high utility of soil as a trace evidence, it is potential to provide information about crimes still have not been fully utilized due to a low number of capacity personnel (Fitzpatrick & Raven, 2012). To conclude, soil evidence can be used in a range of situations to link the murderer to the investigation area and with more research and databases it can be still more useful in the future.

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