Red stains

Published:

Introduction

The item was received in lab N804 at 9.05 am. The purpose of the examination was to look for blood and any other evidence present on the item. Before the examination was carried out the correct lab attire was put on (lab coat, gloves) and the bench washed down with ethanol. Brown paper was then laid on the desk, shiny side up to allow any fibres and other evidence which falls off to be easily spotted. The item was contained in an unsealed plastic bag and had no label on it. The bag was opened with a scalpel and the item placed on the brown paper. The item was a blue BHS t-shirt. The t-shirt was size small and 60cm long. The top half and back was a light blue and the bottom half of the front a dark blue.

There were several red stains on the front of the t-shirt. There were 12 stains on the top of the t-shirt around the collar and 5 on the bottom on the right hand side. There was also a stain only visible under UV light near the shirts collar. On the rear of the t-shirt there were two fibres, one near the top and one near bottom. No evidence was found on the inside of the t-shirt. The examination finished at 11.30 am and the item was sealed in its bag.

Materials and Methods

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The examination started with a visual inspection of the item to find any possible evidence. This was done under a magnifying glass and light. Any possible evidence was marked down on the diagram.

The Red stains were tested for blood initially using the Kastle-Meyer test, which presumptively tests for blood, as described in Lee et al (2006). The stains where then confirmatory tested for blood using the Takayama test as mentioned in Virkler and Lednev (2009).

The hairs and fibres were extracted and placed on microscope slide, as viewed under a light microscope so it can be compared to reference samples and identified as mentioned in Jackson & Jackson (2008)

The item was then viewed under UV light, as this makes stains impossible or hard to view visible. The stain only visible under UV light was presumptively tested for semen using the Acid Phosphate test as described by Virkler and Lednev (2009) and presumptively tested for urine using the DMAC test. The stain was also confirmatory tested for semen using light microscopy and haematoxylin and eosin staining as described by Chapmen et al (1989).

Results

My results show that the red stains on the top of the t-shirt are blood and the red stains on the bottom of the t-shirt were not blood. The stain that's only visible under UV light is neither semen nor urine. The hair found is probably human and the fibre is cotton.

What Next

The blood samples have been sent for DNA analysis to identify from whom the blood came. This will be done by extracting the DNA from the stain using an extraction kit such as QIAamp and amplified using SGM Plus (Clark et al, 2009). The resulting profile will then be compared to the profile of the victim, any suspects and all the profiles on the national DNA database.

The hair does not have a root on it and therefore DNA extraction will be very difficult (Birngruber et al ,2009). However, its morphology can be compared to hair samples from the victim and the suspects to see if they match or not. The hair will also be analysed using GC/MS to identify any drug history of the person it belongs to. (Tsanaclis and Wicks, 2007). The fibre has been been sent for further microscopic and chemical analysis to confirm that it is cotton and to possibly match it to any samples from the suspect or the victim. One such chemical test will be chromatography of the dyes. (Jackson & Jackson, 2008)

References

  • Birngruber, C. Ramsthaler, F. Verhoff, M. (2009) The color(s) of human hair-Forensic hair analysis with SpectraCube. Forensic Science International 185, pp19-23
  • Chapman, R. Brown, N. Keating, S. (1989) The isolation of spermatozoa from sexual assault swabs using Proteinase K. Journal of the Forensic Science Society 29, pp 207-212
  • Clark, D. Hadi, S. Iyengar, A. Smith, J. Garg, V. Goodwin, W. (2009) STR data for the AmpFLSTR SGM Plus loci from two South Asian populations. Legal Medicine 11, pp 97-100
  • Jackson, R. Jackson, J. (2008) Forensic Science 2nd edition. Harlow: Pearson Education Limited
  • Lee, J. Levy, M. Walker, A. (2006) Use of a forensic technique to identify blood contamination of emergency department and ambulance trauma equipment. Emergency Medicine Journal 23, pp 73-75
  • Tsanaclis, L. Wicks, J. (2007) Patterns in drug use in the United Kingdom as revealed through analysis of hair in a large population sample. Forensic Science International 170 , pp 121-128
  • Virkler, K. Lednev, I. (2009) Analysis of body fluids for forensic purposes: From laboratory testing to non-destructive rapid confirmatory identification at a crime scene. Forensic Science International 188, pp 1-17
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