Development of Forensic Science Methods

The Criminal Justice System of England in the 18th century initially consisted of perpetrators being privately prosecuted by their victim, with the victims playing the role of the criminal investigator; gathering and submitting evidence, paying fees to cover the expenses of the constable’s time in order to apprehend the suspect, filing charges with the local magistrates and presenting evidence to the grand jury. However, the development of the CJS has resulted in professional bodies gathering and submitting evidence, alongside the representation of victims in court by the Crown Prosecution Service (CPS), victim support services and there are an array of specialist courts in existence who handle cases specific to their knowledgeable subject.

The Contribution of Forensic Science to Police Investigation

As cited by Pyreck (2007, p. 4), The National Institue of Justice (NIJ. 1998) defines forensic science as “the application of scientific knowledge to the legal system.” Thornton (1997) observes, ” ‘Forensic’ comes to us from the Latin forensus meaning ‘of the forum.’ In ancient Rome, the forum was where governmental debates were held, but it was also where trials were held. It was the courthouse. So, forensic science has come to mean the application of the natural and physical sciences to the resolution of conflicts within a legal setting.” The Home Office Report (2005, p. vii) proposes that “factors such as the degree of integration and communication between police and scientific support appeared to be important in determining retrieval rates.” Forensic science was initially a conventional means to corroborate suspected offenders, however due to procedures such as DNA testing; the report goes on to state that there is an increase in the “proportion of volume crime offences detected using forensic evidence. In the UK, it is estimated that, for directly detected volume crimes, the main evidence securing the detection was forensic in more than one quarter of cases.” Databases such as AFIS and NDNA run systems which provide comparable results from forensic evidence to apprehend offenders on the system; with a detection rate of attaining perpetrators in seven in ten cases, which can render to be the solution to a further 0.4 open cases on the system. Fingerprint evidence can be found 41% of the time at scenes of vehicle crimes, 45% of non-residential burglaries and one in three residential burglary scenes; with 10% of scenes providing DNA evidence. However, it proves to be difficult to collect forensic evidence when scenes are inaccessible, have been purged or the offender has been vigilant. It can also be difficult to convict suspects with a positive DNA match when there is insufficient evidence or the individual provides a legitimate alibi. The use of forensic measures in court however, have proven to impact cases in a positive light; namely for theft, murder and burgulary cases, with an increase of 17% for burglary; alongside this, the appraisal of DNA and fingerprint evidence augments a jury’s decision to convict in cases of homicide and rape.

Methodology Applied when Gathering Blood Spatter Evidence and Other Samples in Criminal Investigation

Forensic Scientists can gather a more accurate profile of the perpetrator and how the crime was committed by gathering and analysing the following specimens:

• Hair analysis
• Fiber Analysis
• Glass Fragments
• Paint Chips Analysis
• Soil Analysis
• Ballistics
• Toolmarks
• Bitemarks
• Fingerprints
• Footwear
• Tire Impressions
• Blood Spatter Analysis
• DNA Analysis
• Blood, Semen, and Saliva (DNA matching and typing; blood-spatter analysis
• Nonhuman DNA (dog, cat, deer, whales)
• Drugs (drug identification, forensic pathology)
• Explosives (bomb and arson identifications and source traces)
• Fibers (fiber typing, source identification, and matching)
• Hair (hair typing and matching)
• Fingerprints (fingerprint matching, AFIS, etc.)
• Bones (gender and age typing, identification of remains; weapon identification)
• Wound analysis (weapon typing; physical movement patterning)
• Firearms and ammunition (ballistics and tool-mark identification)
• Powder residues (shootings, suicides)
• Glass (glass typing and matching)
• Foot, tire and fabric impressions (impression typing and matching)
• Paint (paint typing and matching in automobile collisions, hit and run)
• Petroleum products (product typing and matching)
• Plastic bags (typing and matching; garbage bags as suffocation device or when used in transports)
• Soils and minerals (mineral typing and matching; forensic geology)
• Tool marks (tool identification and matching; homicides, burglary, home invasions, etc.)
• Wood and vegetative matter (plant typing and matching; plant DNA)
• RAPD matching; limnology, Forest Service Lab
• Insects, larvae, maggots; forensic entomology; time of death; location analyses)

(Kiely, F. T. 2006, p. 50)

“One of the underlying principles behind forensic analysis is the concept that when two individuals come in contact with one another, or if an individual comes in contact with an object, there is a high probability of transfer of biological material (skin, hair, etc.). The transfer does not always have to be as obvious as blood”, (Missouri State Highway Patrol, p. 22). Due to this, it is important to collect samples from all those whom have been in contact with the victim and the scene of the crime to avoid wrongful implications by eliminating those individuals whom do not match the suspect’s DNA profile.

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Analysing Blood, Semen and Saliva Samples

“Hair is a biological specimen of the body and may be associated back to its source through DNA analysis (although DNA is not always successfully extracted from hair)”, (Missouri State Highway Patrol page. 30). Alternatively, materials stained with blood, semen, saliva can be collected, be ensured to be air dried before placed in a paper bag and sealed, then tagged with the identification of the contents, exhibit number, initial and date. For porous material such as cloth and leather, investigators are advised to cut the area containing the stain; however for nonporous materials such as glass and metal, stains are removed via a cotton swab that has been moistened with water; and for liquid stains, a clean cotton swab is immersed in the sample. In terms of collecting semen samples, when the specimen is not drying-out, alternatively, condoms are to be frozen. When collecting a Buccal (Oral) swab, two to four swabs must be vigorously rubbed on the interior of the cheek for a minimum of 30secs to a minute to recover epithelial (skin) tissue; which must then be labelled with the individual’s names.

The Application of Fingerprint Identification

“When fingerprint evidence found in a body of water is collected, it should remain in the original water. A watertight container should be lowered into the water and allowed to fill. This allows the evidence to be placed in the container without exposing it to the air. If fingerprint evidence found in water is allowed to dry before processing, the likelihood of developing prints of value dramatically decreases.”

(Missouri State Highway Patrol) page. 17)The Automated Fingerprint Identification System (AFIS) is a database which stores fingerprints that have been taken from suspects, whether they have been incarcerated or not; due to which perpetrators are easily identified, without having a definitive suspect, as their prints are already present on the system. “Latent fingerprints on nonporous materials deteriorate rapidly upon prolonged exposure to high temperature and humidity. Consequently, items should be processed and/or forwarded to a laboratory as soon as possible … A ruled scale should be used when photographing latent prints”. Latent prints on materials are to be handled with gloves and placed in a cellophane protector, whereas latent prints on surfaces such as plastic cards, metal plates and glass bottles are dusted with finger print powder and then extracted with “lifting tape and placed on a 3″ x 5″ card, which contrasts in color with the dusting powder used.”

Behavioural Science Support

As cited by Alison and Rainbow (2011), “the crime scene is presumed to reflect the murderer’s behaviour and personality in much the same way as furnishings reveal the homeowner’s character” (Douglas et al., 1992: 21)

(Alison, L. and Rainbow, L. 2011 p. 19)

• Full verbal case briefing and access to the SIO/investigation team
• All relevant statements
• Crime reports
• Any officers’ reports/status reports
• Pathology and forensic reports/findings
• Full set of crime scene and pst -mortem photographs
• Available analysis (e.g. telephony, palynology, entomology, etc)
• Relevant maps

Visit to all relevant scenes; “allows the BIA to gain fuller understanding of the decision-making process of the offender. Such information is not routinely available from (the above mentioned methods), where often the evidential focus is too restrictive to provide the necessary ‘behavioural’ perspective”.

(Alison, L. and Rainbow, L. 2011 p. 25)

Behavioural Investigative Advisors (BIAs) provide a theoretical perspective in investigations via the use of forensic psychology to support investigators by implementing methods such as “crime scene assessment; DNA screening; suspect prioritisation; familial DNA; nominal pool generation; interview strategy; media strategy; offender background characteristics; and investigation strategy,” (Newburn, T. Et al. p.. 658).

In order to perform an accurate evaluation, BIAs require case materials such as:

Please refer to Appendix. 1: Example of the BIA’s work.

The BIA are able bodies whom provide expertise in offender profiling to connect cases where correlating physical evidence is not evident. “The Serious Crime Analysis Section (SCAS) of the NPIA, through their mandate to collect and analyse a range of sexually motivated offences throughout the UK, now has more than 16,500 offences on ViCLAS (Violent Crimes Linkage Analysis System) database,” (Alison, L. and Rainbow, L. 2011 p. 25).

Appendix

Appendix 1: Example of the BIA’s work.

(Alison, L. and Rainbow, L. 2011) Case Study 2, folder 1FF, 194528.jpg