AC 1.3 Explain how evidence is processed
6 MARKS = 29 MINUTES
- How both types of evidence are processed with examples
Types of evidence:
- Physical evidence : tangible materials, observed and collected
- Testimonial evidence : oral or written statements
Process:
- Transfer
- Storage
- Analysis
- Personnel involved
Physical Evidence:
Locard’s Exchange Principle - ‘every contact leaves a trace’
Body fluids and Tissues:
- DNA can be extracted from bodily fluids and tissues and compared to suspects DNA.
Blood:
- Description: Blood can be found at the crime scene on any surface, either
from the suspect or the victim, can help identify either when analysed.
- Collection and Transfer: Collected by SOCO’s, wet blood must be air dried
first, fabric with wet blood must not be folded because blood can transfer to
other parts of the material. Items should be packaged and sent to a forensics
laboratory within 24 hours.
- Analysis: Forensic scientists analyse to see whether its human or not and a
dna profile begins to be created
- Personnel Involved: SOCO’s and forensic scientists
- Case Study: Found Stephen Lawrence’s blood on the collar of the jacket of
Dobson, linking him to the murder
- Semen:
- Description: Often found at crime scenes of sexual or violent nature, can be
found on clothing or bedding
- Collection and Transfer: Collected by SOCO’s, semen must be air dried.
Items must be packaged in a paper bag, then placed in a polythene bag,
labelled and sealed. If a victim has been sexually assaulted, should be
swabbed ASAP by a police surgeon or doctor.
- Storage: Can be refrigerated or frozen
- Analysis: Forensic scientists can estimate the age of the sperm and some
characteristics, can be compared to control sample of offender
- Personnel Involved: SOCO’s, forensic scientists, police surgeon, doctor
- Saliva:
- Description: Can be inflicted by offender into victim in both sexual and
violent crimes
- Collection and Transfer: Bites on victims are swabbed by sexual assault
nurse examiner or by a forensic odeontologist
- Storage: Placed in drying tube in forensics lab
, - Analysis: Forensic scientists can be used for dna analysis
- Personnel Involved: Forensic odeontologist, sexual assault nurse examiner,
forensic scientist
- Skin Flakes:
- Description: Humans are constantly shedding small amounts of skin, can be
found at a crime scene
- Collection and Transfer: SOCO’s can swab, tap and scrape surfaces to try
and discover trace amounts of skin
- Analysis: Forensic scientists analyse for DNA
- Personnel Involved: SOCO’s, forensic scientists
- Hairs and Clothing Fibres :
- Description: Hair of suspect can be found at the crime scene or hair of the
victim can be found on the offender.
- Collection and Transfer: Hair on furniture or hair of offender on victim is
stored in a paper bag, sealed and labelled and sent of to a forensics
laboratory. Fibres must be collected the same way, ideally within 24 hours.
- Analysis: Forensic scientists analyse the hair root to identify the suspect or
the victim. Fibres can be analysed to control samples of clothes.
- Personnel Involved: Forensic scientists, SOCO’s
- Case study: Forensics linked particles in Sarah Payne’s hair to items in
Whiting’s van
Fingerprints:
Fingerprints are unique to the individual, marks can be from sweat or contaminants on the
skin. Fingerprints will be compared to those stored in the IDENT1 database, police
have live scanners and portable units that can link the database to suspects prints in
a matter of minutes.
- Case Study:
- Fingerprint on the inside surface of the cash box was able to be linked and
used as evidence in court against the Stratton Brothers.
- Latent Prints:
- Description: Marks on surfaces that can be made visible by dusting with
magnesium powder or shining ultraviolet light.
- Collected and Transfer: Photographed first by SOCO’s and lifted with
adhesive strip and placed on acetate surface
- Analysis: Compared to DNA database or control sample by forensic
scientists
- Personnel Involved: SOCO’s, forensic scientists
- Parent (positive) prints:
- Description: Fingerprints that are visible to the naked eye, may be left in
blood, ink, oil, powder, dust
- Collection and Transfer: Photographed by SOCO’s at the crime scene and
possibly preserved for court
- Analysis: Photograph is usually analysed by forensic scientist
- Personnel involved: SOCO’s, forensic scientists
- Plastic prints:
- Description: 3D, fingerprints in soft materials, for example clay
- Collection and Transfer: Photographed by SOCO’s and if possible made
into a mould
6 MARKS = 29 MINUTES
- How both types of evidence are processed with examples
Types of evidence:
- Physical evidence : tangible materials, observed and collected
- Testimonial evidence : oral or written statements
Process:
- Transfer
- Storage
- Analysis
- Personnel involved
Physical Evidence:
Locard’s Exchange Principle - ‘every contact leaves a trace’
Body fluids and Tissues:
- DNA can be extracted from bodily fluids and tissues and compared to suspects DNA.
Blood:
- Description: Blood can be found at the crime scene on any surface, either
from the suspect or the victim, can help identify either when analysed.
- Collection and Transfer: Collected by SOCO’s, wet blood must be air dried
first, fabric with wet blood must not be folded because blood can transfer to
other parts of the material. Items should be packaged and sent to a forensics
laboratory within 24 hours.
- Analysis: Forensic scientists analyse to see whether its human or not and a
dna profile begins to be created
- Personnel Involved: SOCO’s and forensic scientists
- Case Study: Found Stephen Lawrence’s blood on the collar of the jacket of
Dobson, linking him to the murder
- Semen:
- Description: Often found at crime scenes of sexual or violent nature, can be
found on clothing or bedding
- Collection and Transfer: Collected by SOCO’s, semen must be air dried.
Items must be packaged in a paper bag, then placed in a polythene bag,
labelled and sealed. If a victim has been sexually assaulted, should be
swabbed ASAP by a police surgeon or doctor.
- Storage: Can be refrigerated or frozen
- Analysis: Forensic scientists can estimate the age of the sperm and some
characteristics, can be compared to control sample of offender
- Personnel Involved: SOCO’s, forensic scientists, police surgeon, doctor
- Saliva:
- Description: Can be inflicted by offender into victim in both sexual and
violent crimes
- Collection and Transfer: Bites on victims are swabbed by sexual assault
nurse examiner or by a forensic odeontologist
- Storage: Placed in drying tube in forensics lab
, - Analysis: Forensic scientists can be used for dna analysis
- Personnel Involved: Forensic odeontologist, sexual assault nurse examiner,
forensic scientist
- Skin Flakes:
- Description: Humans are constantly shedding small amounts of skin, can be
found at a crime scene
- Collection and Transfer: SOCO’s can swab, tap and scrape surfaces to try
and discover trace amounts of skin
- Analysis: Forensic scientists analyse for DNA
- Personnel Involved: SOCO’s, forensic scientists
- Hairs and Clothing Fibres :
- Description: Hair of suspect can be found at the crime scene or hair of the
victim can be found on the offender.
- Collection and Transfer: Hair on furniture or hair of offender on victim is
stored in a paper bag, sealed and labelled and sent of to a forensics
laboratory. Fibres must be collected the same way, ideally within 24 hours.
- Analysis: Forensic scientists analyse the hair root to identify the suspect or
the victim. Fibres can be analysed to control samples of clothes.
- Personnel Involved: Forensic scientists, SOCO’s
- Case study: Forensics linked particles in Sarah Payne’s hair to items in
Whiting’s van
Fingerprints:
Fingerprints are unique to the individual, marks can be from sweat or contaminants on the
skin. Fingerprints will be compared to those stored in the IDENT1 database, police
have live scanners and portable units that can link the database to suspects prints in
a matter of minutes.
- Case Study:
- Fingerprint on the inside surface of the cash box was able to be linked and
used as evidence in court against the Stratton Brothers.
- Latent Prints:
- Description: Marks on surfaces that can be made visible by dusting with
magnesium powder or shining ultraviolet light.
- Collected and Transfer: Photographed first by SOCO’s and lifted with
adhesive strip and placed on acetate surface
- Analysis: Compared to DNA database or control sample by forensic
scientists
- Personnel Involved: SOCO’s, forensic scientists
- Parent (positive) prints:
- Description: Fingerprints that are visible to the naked eye, may be left in
blood, ink, oil, powder, dust
- Collection and Transfer: Photographed by SOCO’s at the crime scene and
possibly preserved for court
- Analysis: Photograph is usually analysed by forensic scientist
- Personnel involved: SOCO’s, forensic scientists
- Plastic prints:
- Description: 3D, fingerprints in soft materials, for example clay
- Collection and Transfer: Photographed by SOCO’s and if possible made
into a mould
