UNIT 3 AC 1.3
Physical evidence
Evidence admissible in caught
The difference between testimonial evidence and physical evidence is that testimonial evidence given by victims,witnesses and even offenders at first hand where as physical evidence is evidence within the crime scenes and outside areas also etc like the murder weapon or hairs fingerprints etc.
Locard exchange principle: Locard explains how evidence is exchangeable between suspects, victims and the environment. Locard believes how important it is to find and process evidence found.
Also that the offender will have at least one piece of evidence on them from the crime scene even the smallest particle can link a suspect to the crime.
Bodily fluids:
To ensure evidence is not contaminated on the way to a forensic laboratory the individual transporting it back and collecting it must wear protective clothing. This is to make sure that the individual is protected in case the area is hazardous and to make sure that their DNA is not transferred to the evidence contaminating it which would make it useless. Less serious crimes people such as CSI have to wear gloves and masks.
Blood: should be carefully packaged and sent straight to the forensic lab within the first 24 hours for analysis. This can provide a scenario on how the crime happened and being able to replay the murder through blood splatter, where patches are and how fresh the blood is over other injuries of the victim has sustained. Maybe even lucky enough to have the DNA of the offender if the victim fought back maybe leaving some traces on the victim.
Saliva: If the victim bite the offender the police can swab the saliva for DNA analysis to get a match leading to an arrest.
Semen: if wet needs to be left to dry then once this is done it must be carefully sealed and labelled and sent to the lab to be analysed as DNA can be traced and connected to possible suspects maybe even getting a match. A doctor or police surgeon does this analysis/examination.
Skin flakes: if found on the victim or suspect then this can be traced for DNA allowing the smallest little flake leading to the arrest of the offender as most criminals don’t think of skin flakes being left.
Hairs: if hairs are left the offender this can be tested against suspects hopefully getting a match, these are normally left at the crime scene unknown to the offender. Hairs found must be wrapped in paper and placed in a paper bag, sealed and sent to forensics to be tested. Also DNA can be traced to suspects on the criminal database that’s if they’ve been arrested in the past. Hair can link to the victim also.
Fingerprints:
Everyone has their own individual fingerprints that if left at crime scenes can be collected and Analysed which then can be traced through different criminal databases hopefully getting a match this is only if the offender has committed a crime in the past if not there will be no trace.
Latent prints: invisible to the naked eye but if magnesium powder is wiped over the print and a UV light is used to see and collect the print through the use of adhesive strip.
Patent prints: These are visible and can be found in many different locations in a crime scene for example blood,oil,powder,dust etc. Then it can be photographed and taken for analysis.
Plastic prints: These can be found in 3D shapes for example on a window frame which then a mould can be made for analysis.
Impression evidence: is evidence of when the suspect presses against a surface and then something is left behind e.g fingerprint or DNA etc.
Bite marks: saliva can be collected by the bite marks which can be tested for DNA of the offender these are most sexual attacks. Also a bite mark can be cast to then compare to suspects bites by special dentists who can find a match if there is one.
Shoe prints: if footprints are left in blood, soil etc this can lead to cast being made which can trace back to suspects size and type of shoe that was used in the crime. The police have a national footwear reference collection which can identify if a suspect in custody has similar footwear or identical footwear.
Tyre marks: left on roads and soil which can be analysed being able to track the types of cars that use these types of tyres and tread also helps to narrow this down. Also if suspects have vehicles of their own these tyre marks can be used to check if they are the same tyres as each tyre has its own characteristics as it wears.
Trace evidence: anything the suspect left at the crime scene can be traced back to its original owner or location for example physical evidence like gunshot residue or toxicology for example drugs,alcohol etc.
Fibres: Can be natural or synthetic. Which fibres can be transferred from clothing, carpets and seats. They can be collected using gloves and tweezers and sent for analysis. Fibres from clothing come in a wide variety of fabric mixes and dyes, often specific to manufacturers. This could lead to the garment they came from being found and this information may be used in compiling a description of the suspect.
Paint: many different types and colours of paint which can lead to the identification and matching of flakes found on the suspects clothing, tools etc.
Glass: Can be identified on suspects clothing if glass fragments get stuck in their clothes and pattern can be found leading to evidence and trace that they committed the crime.
Soils: soils found on clothing and footwear can place suspects at the crime scene.
Insects: The different amount of insects within the dead bodies can give a good estimate of the time of death which is a major piece of evidence. A forensic entomologist examines this.
Testimonial evidence
Vulnerable witnesses such as anyone under 18 or with mental health issues etc are allowed to provide evidence via video rather than in person to protect them for example the John venables and Robert Thompson who killed a child which they were both too young to go to court and did there case through video link to protect them as they were young.
This type of evidence is spoken or written which is given by the witness to the court before this can happen though both the prostitution and the defence had to disclose there witness statements. Also they must list there witnesses to the court so they can be called up in the trial to provide the evidence.
Both sides must agree with each other evidence for it to be submitted to the court and to testify their evidence. Both prosecution and defence look at each other’s evidence and can only ask questions related to case and trial.
Hearsay: such as rumours the witness may spread to convince the jury to give a guilty verdict than actually telling what actually they saw. Sometimes this happens through the media getting hold of this information and rumours.
Forced confession: This is when the defendant has been threatened or under threat to give a false confession due to fear not giving a truthful confession.
Entrapment: When the police trick the defendant into confession so prosecution and prosecute them.
Disclose is when someone makes new or secret information known. For example a
a judge may order the disclosure of companies documents meaning anything found may be admissible in caught.