CRM105 Introduction To Criminal Justice

Physical Evidence

Physical evidences are the any kind of evidence that can be physically obtained in the scene of crime. These evidences are also called the real or material evidence. The physical evidence tends to play a vital role in the formation of the litigation charges and can be produced in case proceedings as a support in forming a conclusive decision for a case. The chief types of physical evidences that are collected from a scene of crime involves fingerprints, footprints, marks of tire or biological evidences like the DNA samples that are collected from the body parts of fluids as they also form a subcategory of the physical evidence. The Rule 401 of the Federal Rule of Evidence discusses the concept of evidence (Carroll 2009). This section states that evidences are facts the presence of which can make a conclusive decision in generating a decisive result of a case.

Types of Physical evidence in the crime scene

There are different types of evidences that can be collected from the turn-a-round lounge depending on the nature of crime.

Fingerprints: the fingerprint in most of the cases are visible without the aid of any devise in case they are not visible to the bare eyes than they are called latent fingerprints. The latent fingerprints have been collected from the crime scene of the Turn-a-round lounge. These types of evidences are chiefly generated from the sweat or oil coming from the skin. Latent fingerprints are visible from the other lighting sources that are used. It is notable that the hands and feet don’t have any oil glands as a result latent fingerprints of hands and legs can be considered to be coming from other sources. It is also to be noted that the cold hands tend to leave less strong finger prints in comparison to warm hands. In case someone in engaged in fighting activities the chances of generating body heat is higher so this types of evidence can be considered to be of importance in this case. The presence of the fingerprints or footprints of a person in a place can be considered as significant evidential proof of the person being present at the scene of crime. There are different types of fingerprints that can be collected like patent fingerprint which are prints of other material on body parts which is in turn printed in some location of the crime scene. The plastic fingerprints which are prints of hands and legs that are on a soft surface like liquid or semi solid substance (Bhargava et al. 2009). Bloody footprints are impressions that are formed from source of blood which ends up making marks in some other substance. This evidence has also been available in the Turn-a-round lounge’s crime scene in terms of blood stained footprints which were present in the exit of the place. It is also notable in this case that there were three footprints that have left the location of crime in turn-a-round lounge. These types of physical evidence are considered as conclusive in nature in a case.

Impression evidence: impression evidences involve marks that are formed when there is a significant level of contact between two objects that leaves evidential impression. The patterns that were formed by the tyre of the car of Sam and Michelle in the mud parking of the lounge can be considered under this type of evidence. The imprints that are formed in the mud because of the pressure of the tyre can provide classification information like type of vehicle, pattern of the vehicle and the possible direction of the motion of the car (Bhargava et al. 2009). The ‘Tire book’ which provides information regarding around 5000 different tyre prints can provide evidential proof regarding the identity of the tyre as well as the possible track that is taken by the vehicle.

Trace evidence: the searching of the trace evidence is one of the most important aspects of the forensic investigation. Trace evidences can cause to develop conclusive evidences that can help in deciding the case. The trace evidences involve substances that are likely to be overlooked unless microscopic investigation is done. This can involve cloth fibres, hairs, dirt material etc. The Locard’s Exchange principal states that a person cannot be in interaction with a situation without collecting any evidence from it or leaving any evidence of his or her presence in that place (Tedeschi 2013). Trace evidence involves traces on the body of the victim, small fabric of clothing, trace evidences from foot wares, footprints on floor, traces of metal, weapons in this case the knife and biological trace evidences.

Documentary evidence: the documentary evidences involve papers and writings. In this murder case threatening letters were claimed to have been written by Joe the victim. They were found in the house of one of the suspects that is Michelle.

Sections of forensic science labs

Latent fingerprint section: the latent fingerprint section of the forensic lab uses several chemical and non chemical procedures to determine the fingerprints. The fingerprint section of the forensic laboratory also involves activities like using of the international fingerprint database to recognise the person whose fingerprint has been collected (Tedeschi 2013).

Trace evidence section: the trace evidence section takes into consideration traces of evidences that are microscopic in size. This section is highly dependent on microscopy, FTIR microscopes, electron microscopes etc (Robertson Vignaux & Berger 2016).

Forensic Garage: the tire impressions and the possible structure and model of the car can be examined in the forensic garage section. This section deals with all information regarding the detail of cars. They are chiefly responsible for the processing of evidence regarding the impression that is made by the wheels of the car in this case (Saferstein 2013). These are also called the examination area for vehicles involved in a crime scene.

Questioned documents lab: This is the section of forensic lab that conducts investigation regarding papers and inks that has been collected as evidences in the investigation of a case. This section also takes into consideration the verification of the authenticity of the document that has been presented as evidence in solving a case (Siegel & Saukko 2012). In this murder the threatening letters of the victim that is Joe has been found in the house of one of the suspects that is Michelle during the investigation. Michelle claimed that the letters were written by Joe however the documents lab can confirm the authenticity of the document. 

Reference

Bhargava, R., Perlman, R. S., Fernandez, D. C., Levin, I. W., & Bartick, E. G. (2009). Non-invasive detection of superimposed latent fingerprints and inter-ridge trace evidence by infrared spectroscopic imaging. Analytical and bioanalytical chemistry, 394(8), 2069-2075.

Carroll, J.L., (2009). Proportionality in discovery: A cautionary tale. Campbell L. Rev., 32, p.455.

Robertson, B., Vignaux, G. A., & Berger, C. E. (2016). Interpreting evidence: evaluating forensic science in the courtroom. John Wiley & Sons.

Saferstein, R. (2013). Forensic Science. Pearson/Prentice Hall.

Siegel, J. A., & Saukko, P. J. (2012). Encyclopedia of forensic sciences. Academic Press.

Tedeschi, J. T. (Ed.). (2013). Impression management theory and social psychological research. Academic Press.