ac1.3 Flashcards
What is meant by the term ‘testimonial’ in relation to criminal evidence?
Verbal evidence and opinions from experts, eyewitnesses, pathologists, scientists, detectives.
What is the Locard’s exchange principle?
A theory relating to a transfer of trace evidence between objects, stating that “every contact leaves a trace”. The theory dictates that when two objects come into contact with one another, each will take something from the other object or leave something behind.
What is meant by, ‘rules of evidence?’
The rules and legal principles that govern the proof of facts in a legal proceeding. These rules determine what evidence must or must not be considered by the trier of fact in reaching its decision.
What is meant by the term, ‘vulnerable witness?’
a witness who can be more easily attacked in traditional adversarial court proceedings. Particular legislation in particular jurisdictions at particular times may include or exclude various categories of individuals. Core examples include children, and those with mental problems.
what is hearsay evidence
where a witness is repeating a rumour, they have heard rather than describing what they themselves saw.
what is forced confession
where violence or threats have been used to extract a confession from the defendant.
what is entrapment
where the police have tried to trick the defendant into committing or confessing to a crime in order to be able to then prosecute them like in the ‘honey trap’ in the case of Colin Stagg.
how should blood stains be collected
Blood should be allowed to air-dry. Fabric bearing wet blood shouldn’t be folded, as this will cause the blood to transfer to other arts of the item. Items with dry blood on them should be carefully packaged and sent asap and in any event within 24 hours to the forensics lab for analysis.
how should semen stains be collected
Semen may be found on clothing and bedding. If wet, it should be allowed to air-dry on the item. Once dry, the item should be placed in a paper bag, which should then be sealed and placed inside a polythene bag, again sealed, and labelled. Each item should be packaged separately. Where someone has been the victim of sexual assault, they should be examined as soon as possible by a police surgeon or other doctor and swabs taken.
how should Hair samples be collected
If hairs are found on clothing the item should be wrapped in paper, placed in a bag, sealed, labelled, and sent to the forensics laboratory for analysis. Individual hairs found on furniture should be wrapped or bagged in the same way. DNA can be extracted from cells in the root to identify suspects or victims.
how should Fibres and threads be collected
These fibres can be natural or synthetic. They can be transferred from clothing, carpets and seats. They can be collected using gloves and tweezers, wrapped in paper and sealed in a bag, labelled and sent for analysis. Fibres from clothing come in a wide variety of fabric mixes and dyes, often specific to particular manufactures. This can aid in identifying the garment it came from and the information may be used in compiling a description of the suspect.
how should fingerprints be collected
This is valuable evidence as everyone has unique fingerprints, the prints are skin ridges on the fingers and they can leave impressions or marks in or on the surfaces. The marks can be from sweat or from contaminants on the skin. There are three different types of prints: latent, patent, plastic. Latent prints are invisible marks left on a surface that can be made visible by ‘dusting’ with magnesium powder or shining an ultraviolet light on the surface. After photographing them, prints may be lifted using an adhesive strip and placed on an acetate sheet. Patent prints are visible to the naked eye. They may be left in substances such as blood, ink, oil, powder or dust. They should be photographed for analysis and if possible preserved for use in court. Plastic prints are 3D shapes made by pressing the fingers into soft materials such as wet clay or the putty on a window frame. They should be photographed and if possible, a mould made to capture a copy of the impression.
Once collected from the crime scene, fingerprints can be compared with those stored in the police’s IDENT1 database, which houses prints of all arrested persons, to see if there is a match. Police also have live scan scanners and lantern portable units linked to the database that can scan suspects’ prints and obtain a result within minutes.
how should shoe prints be collected
Left in oil, paint, blood etc. can be used to seek a match with a suspect’s footwear. If prints are left in soil, casts can be made. Outdoor prints should be protected from the weather until they can be properly examined. The police have a database called the National footwear reference collection which can be checked to see if they match a known offender’s footwear.
how should bite marks be collected
Bite marks on victims often result from sexual assaults. As they often contain traces of the suspect’s saliva, they should be examined promptly by a police surgeon and swabs taken for DNA analysis, and the marks should be photographed. It may be possible to take a cast of the bitemark to compare with one taken of a suspect’s teeth, which can be analysed for a possible match by a specialist dentist called a forensic odonatologist.
what is meant by patent evidence
evidence in crimes that can be gathered. obvious
