Unit 3: AC 1.3

Alternative transcript:

as a silent witness against him. Not only his finger prints or his foot prints, but his hair, the fibres from his clothes, the glass he breaks, the tool mark he leaves, the paint he scratches, the blood or semen he deposits or collects. It is factual evidence. Physical evidence cannot be wrong, it can not be wholly absent. Only human failure to find it, study and understand it can diminish its value.' Collecting, transferring and storing physical evidence: Types of physical evidence need to be collected, transferred, and stored- to avoid contamination. Contamination mostly comes from handling items without gloves, or by breathing, coughing or sneezing over them. In serious crimes like murder/rape- investigators collecting material wear protective clothing to avoid contamination and protect themselves from hazardous substances. They wear a mask, hooded 'scene suit', overshoes and 2 pairs of gloves. Less serious crimes only need masks and gloves. Bodily fluids and tissues: DNA can be extracted from bodily fluids like blood, semen, and saliva, as well as from tissue like skin flakes and hairs. This makes them a useful source of identification, as samples are compared with control ones from suspects, to see if a match puts the suspect at the crime scene. Blood- ● ● Semen- ● ● ● ● Allow to air dry. Fabric with wet blood not to be folded, as this causes blood to transfer to other areas of the item. Items with dry blood should be packaged carefully, and sent to the forensic laboratory for analysis as soon as possible. (within 24hrs) Saliva- Hairs- May be found on clothing and bedding. Should be allowed to air dry on item if wet. Items should be placed in a paper bag once dry, then sealed and put in a polythene bag that will also be sealed and labelled. Each item is packaged separately. If someone is a victim of sexual assault, they should be examined as soon as possible by a police doctor/other doctor- swabs taken too. Skin flakes- ● People constantly shed small amounts of skin. ● These can be found at the crime scene and analysed for DNA. ● Bites on a victim can be swabbed to have a sample for DNA analysis. Can be found at crime scene and matched to a suspect. Victim's hair may be found on the suspect in an assault case. Hair found on clothing should be wrapped in paper/put in a paper bag, and then sealed, labelled, and sent for lab analysis. • Single hairs found on furniture can be collected in the same way. DNA can be extracted from cells in the root to identify suspects/victims. Fingerprints: ● Finger, palm, toe, and sole prints are unique to each person, so they are useful identification evidence. The 'prints; are skin ridges on the fingers and they can leave marks/impressions on surfaces. The marks are from sweat or contaminants on the skin. There are 3 kinds of fingerprints: Latent prints: invisible marks left on a surface that are made visible with a UV light or a dusting of magnesium powder. After they're photographed, prints can be lifted using an adhesive strip and placed on an acetate sheet. Patent (or positive) prints: visible to the naked eye, may be left in substances like blood, ink, oil, powder or dust. They should be preserved in court if possible, and photographed for analysis. Plastic prints: 3D shaped made by pressing fingers into soft material like clay or the putty on a window frame. (plastic here means easily shaped or moulded). They should be photographed and if possible, a mould made to get a copy of the impression. Once fingerprints are collected, they can be compared with ones stored in the police's IDENT1 database, which has prints of all arrested persons, to see if there's a match. Police have Livescan scanners and Lantern portable units linked to the database that can scan suspect's prints and obtain a result within minutes. Impression evidence: This type of evidence is created when a suspect 'presses' something against a surface. This can be a hand, like fingerprints, or an impression can be made by biting someone, or leaving a shoe/tyre mark. Bite marks: victims often get these from sexual assaults. Police surgeons should quickly examine them and swab them, as the bite contains traces of the suspect's saliva for DNA analysis. The marks should also be photographed, and a cast of the bite should be made if possible so it can be compared to the suspect's teeth, analysed for a match by a forensic odontologist. Shoeprints: left in oil, paint, blood, etc. Can be used to try and match a suspect's footwear. Cast should be made if the print is in soil, and outdoor prints should be protected from the weather until they're examined. The police have a database (National Footwear Reference Collection)- prints can be matched to a known offender. Tyre marks: left in soil, on roads, etc, can be made by a rotating/skidding wheel. As they wear, tyres develop individual characteristics, which means they can be compared to the suspect's. Trace evidence. This is any material transferred from suspect to crime scene and/or victim. Examples: gunshot residue, glass fragments, paint flakes/fibres, soil, and insects. Also includes: toxicology- poisons, drugs, and alcohol, eg: from roadside breathalyser tests. 1. Fibres: Can be natural or synthetic, and can be transferred from clothing, carpets, and seats. ● Collected using gloves/tweezers, are then wrapped in paper and sealed in a bag, labelled, and finally sent for analysis. ● Clothing fibres vary in fabric mix, dyes, and can be specific to a manufacturer. This can help identify the garment they came from- info that helps build a description of a suspect. 2. Paint: ● Can be on window frames, doors, cars. Also other objects in different colours/types, like rustproof, weatherproof, and antifungal. ● This helps identification and allows matches to flakes found on a suspect clothing, tools, etc. 3. Glass fragments: Found at break-ins, can be compared to fragments on suspect's clothing. The glass in smashed windows undergoes 'backward fragmentation'- this throws fine particles at the person breaking the window. These land on the person in a certain pattern, therefore showing they were present when it broke. ● ● ● ● 4. Soils: Can vary a lot, even over short distances. ● This means soil on a suspect's footwear can place them at the scene. Case study- Barry George/ murder of Jill Dando ● Jill Dando was the presenter of Crimewatch, and was shot dead outside her home in April 1999. 5. Insects: ● This could be blowflies, which lay eggs on dead bodies. This can give an indication of the time of death, by a forensic entomologist examining how developed the larvae/maggots are. ● Barry George was arrested and charged with her murder in May 2000, convicted in July 2001. Part of the case against him was trace evidence. It was a single microscopic particle of gunshot residue- found in his overcoat pocket after 1yr after the murder. The prosecution argued this came from a gun George fired. In 2006, George appealed the case on the grounds that 2 new witnesses said they saw armed police at the scene of his arrest. The police had claimed no armed officers were present. The defence called forensic experts (as well as ones from the original trial), who told the Court of Appeal that it was no more likely that the residue was from a gun fired by George than from some other source. They then argued that the armed officers at his arrest could've been the source of the residue. The court quashed George's conviction and ordered the retrial that acquitted him in 2008. Testimonial evidence: This is a written/spoken statement given to the court by a witness. It is given to support either the prosecution or the defence's case. Disclosure: Before the case goes to court, prosecution and defence must disclose any written statements they've taken. Each side must provide each other with a list of the witnesses they intend to call to give evidence at the trial. Physical evidence like CCTV footage also has to be disclosed. Giving evidence: Evidence agreed and accepted by both sides to be true can sometimes be read in court without the witness there. But usually, they have to be there in person so they can testify. ● Witnesses testify in court from the witness box. Then they may be cross-examined (questioned) by the opposing side to test their evidence. Defendants cannot be forced to testify. Vulnerable/intimidated witnesses can be allowed to give evidence by a live video link/video recording. And if they do attend, they can be allowed to give evidence from behind a screen. ● Admissibility of testimonial evidence: Rules of evidence define what kind of things can and cannot be given as evidence. Some evidence isn't admissible and mustn't be considered in reaching a verdict. This can be: ● Hearsay evidence- eg- a witness is just repeating a rumour they've heard, instead of describing what they actually saw themself. Forced confession-violence or threats being used to extract a confession from the defendant. Entrapment- police have tried to trick the defendant into committing or confessing to a crime so that they can prosecute them. E.g- the 'honey trap' police set for Colin Stagg was ruled as inadmissible evidence by a judge in court. Case study- Expert testimony, disclosure, and cot deaths cases Sally Clark was convicted of the murder of her 2 sons in 1999, but was aquitted after her second appeal in 2003. Her conviction happened because of 2 serious shortcomings from expert witnesses. ● Dr Alan Williams, the forensic pathologist who performed the autopsies, failed to disclose key evidence. He withheld that the 2nd death could have been the result of infection, and changed his original opinion of the 1st death being respiratory infection, to death by smothering. When the court invited him to explain his withholding of lab results, he declined to do so. The second error came from paediatrician Professor Sir Roy Meadow, who said the chance of the 2 siblings cot death was 1 in 73 million. The Royal Statistical Society later said that there was no statistical basis for this claim, and showed concern about the misuse of stats in court. Meadow testified/made the same claim in 2 other cases, Donna Anthony in 1998, and Angela Cannings in 2002- both cases for the murder of their 2 children. Cannings was freed on appeal in 2003, and Anthony in 2005. Meadow was struck off the medical register for gross professional misconduct in 2005, but got reinstated in 2006.