Forensic Glossary Flashcards
(37 cards)
Definition of biological material ?
Provides links directly to a person. 4 categories:
- Body fluids : blood, semen, saliva
- Trace biological : epithelial cells (i.e. Skin or mouth cells) transferred through contact
- Hairs : hair shaft only, hair with root
- Toxicology : drugs in blood, urine, hair
What is bloodstain pattern analysis?
Bloodstain patterns can be found on a victim, on an assailant ,or Ina surface at the scene . Many types occur:
- cast-off bloodstains ( from implement or weapon )
- pooled blood (from a person lying in one position for a period of time)
- dripped bloodstains ( indicates direction and movement of the victim or assailant )
- splattered bloodstains (indicates impact or blows- may not be visible to the naked eye )
- arterial spurting (indicates injury type)
- backspatter ( from a firearm wound)
- latent blood stains (not evident to the naked eye and require luminal testing but may reveal material vital to reconstruction)
A bloodstain pattern analysis can provide information about the kind of weapon used, or the number of blows inflicted .
Definition of admissible (in relation to evidence)?
Means that evidence is allowable and can be accepted by the court
Definition of chain of evidence?
Record of all the people who have had custody of an exhibit since it was first discovered, to its presentation in court and its security in police records
Definition of cold zone?
Area in outer cordon of scene. Place where O/c scene manages scene examination and staff involved (i.e. Briefings and debriefings, meals, scene records )
What is the reason for zoning a crime scene?
Helps to avoid contamination of the scene and the evidence it holds, also helps manage access to the scene .
Definition of contamination?
Occurs when material is added to an exhibit post incident ( i.e. When animals or humans enter the scene)
Forensic science is underpinned by the principle that ‘ every contact will leave a trace’
Contamination can also occur through the evidence collection and exhibit packaging phase.
Definition of control sample?
Samples of known origin that can be compared with materials found on items being examined. Sometimes called reference samples
Definition of cross contamination?
Occurs through the exchange of traces of forensic material between the offender, the crime scene, the victim and other people
I.e. If offender and victim are transported in same vehicle.
Can also occur through secondary transfer, i.e. when an officer who has dealt with the victim then interviews the suspect.
Definition of degrade?
Over time all biological material will degrade naturally.
Technological developments in forensic science now mean that it may still be possible
to retrieve fingerprints and dna from bodily samples.
Forensic experts must be the people to examine, lift and analyze biological material that has degraded.
Definition of deteriorate?
Forensic evidence will deteriorate under certain conditions.
Example: an offender s shoe that is spattered with blood is packaged in a plastic bag and forwarded for analysis. The sealed bag generates the growth of mould on the surface of the shoe and encourages the blood sample to deteriorate
Example: a bloodstain sample collected from the dashboard of an abandoned car has deteriorated by being exposed to direct sunlight over several days.
Definition of dna?
Deoxyribonucleic Acid, genetic material contained within living things.
DNA a profiles are used to distinguish between individuals.
In a serious crime investigation. DNA samples from a person /people may be voluntarily provided or lawfully compelled and submitted for analysis.
To the DNA databank at ESR
For comparison with a case
What is a DNA profile?
Is generated from the analysis of an individual s DNA sample. Individuals DNA profiles are stored on National DNA database, located at ESR. Contains samples from convicted offenders and volunteers.
Another database is the crime sample database. This database contains DNA profiles from unresolved crimes in NZ
Definition of elimination samples?
Refers to samples (i.e. hair, fingerprints, shoeprints) taken from people who are not connected with the offence but who may have come into contact with the crime scene evidence
Example: footprint below a window is shown to belong to a contract window cleaner
Definition of entomological samples?
Entomology is the science of studying insects. Entomological samples are insect samples collected from a scene that can assist with objective scientific evidence.
Example: insect samples collected from a body can assist with estimations of time of death
Example: insect samples collected from a cannabis plant, or from a package of organic material, can assist in identifying the region of origin of the material
Definition of forensic material?
May be of a biological or physical nature.
Material gathered in an investigation may or may not become forensic evidence.
To be presented as forensic evidence, the material must be analyzed to provide objective and scientific data determining its relevance to the investigation
Definition of golden hour?
Period immediately following the commission of an offence when material is abundant and readily available to police.
Positive action in the period immediately following the report of a crime minimizes the attrition of material and maximizes the chance of securing the material that will be admissible in court.
What are the key considerations for staff conducting crime scene initial action ?
- identify scenes, secure, assess and commence log
- preserve physical evidence
- prevent contamination of victims, scenes, witnesses and suspects
Definition of hot zone?
Area in decontamination zone model. Is party of the scene requiring examination and evidence protection. It is closely controlled by the O/C scene. Exhibits are collected and packaged for forensic analysis in the hot zone.
What is the definition of impressions ?
Evidence of a biological or physical nature that is left at a crime scene. It is a key example of the basic principle of forensic science that every contact will leave a trace.
Impressions generally require specialized collection and packaging.
Examples of impressions: Footwear impressions in soil etc.. Car tyre in soft mud Fingerprint in a colter, fabric impression on a car bumper Tool mark at a place of forced entry
Definition of intangible?
Unable to be touched, not having a physical presence.
Section 97 of S&S act gives examples: email address, information held in an Internet storage facility
Definition of latent samples?
Latent means hidden or concealed.
Used to describe fingerprint or footprints that are present ur not visible to the human eye until revealed through the use of powders or chemicals or special lighting
How is integrity of evidence protected?
-access to the scene is controlled and documented
- forensic examination is conducted by personnel with an acceptable level of knowledge of the scientific method and who are suitably trained or qualified
- the ‘chain of evidence’ is secure
The ultimate test of the integrity of forensic evidence is when it is presented in court.
What is order of examination?
It applies to any exhibit where multiple evidence types are present.
Means the preferred sequence of examination or analysis undertaken on a document exhibit. The order is determined by the investigative need, i.e.which type of analysis is going to be of most evidential value to the investigation
Example: a threatening not eased to a bank teller during a robbery may be forwarded to the document examiner for indentation analysis prior to being examined for fingerprints.
Retrieving fingerprints first will mean any indentations are lost. Fingerprint treatment can also negatively affect document examinations such as ink comparisons, pPer comparisons and physical matching
