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Author Topic: Forensics: Summary Notes  (Read 5659 times)

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caffinatedloz

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Forensics: Summary Notes
« on: December 10, 2019, 09:38:30 pm »
+6
I don't know how many other schools offer this subject, but hopefully, these notes help someone out! ;D ;D

Forensic Science
Definitions
Forensic Science
The scientific method of gathering and examining evidence relating to a crime and matters under legal investigation.

Forensic Psychology
Forensic psychology applies psychology to legal matters and the criminal justice system.

Crime Scene
Any physical location where a crime has occurred or is suspected of occurring.

Anthropology
Recovery and identification of skeletal remains.

Entomology
Collection and study of insects, particularly larvae and maggots to determine the time of death.

Geology
Collection and study of soil and mineral evidence.

Odontology
Study of dental remains and bite marks.

Serology
Collection and study of DNA in blood, semen, saliva, vaginal fluids (and other bodily liquids).

Dactology
Collection, study and identification of human fingerprints.

Pathology
Conduction of autopsies.

Podiatry
Collection and examination of footprints (and shoe prints).

Psychology
The study of characteristics of perpetrators.

Chemistry
Collection and study of accelerants and gunshot residue.

Toxicology
The study of the influence of drugs and poisons on the body.

Crime Scenes
When arriving at a crime scene, certain procedures must be followed. When an officer arrives at a scene they ensure that no one is in immediate danger before securing the scene. Evidence is photographed before being bagged and collected.

Types of Evidence
Testimonial Evidence
Oral or written statements given to police as well as court testimony by people who witnessed an event.

Physical Evidence
Any material items that would be present at a crime scene.

Trace Evidence
Physical evidence found in small but measurable amounts.

Trace Evidence
Locard's Exchange Principle is that: "Every contact leaves a trace." Trace evidence is evidence that is found in small but measurable amounts.

Blood
Blood Types
Type A: A antigen, B antibody
Type B: B antigen, A antibody
Type AB: A and B antigens, no antibodies
Type O: no antigens, A and B antibodies

Blood Spatter Analysis
- Blood falling vertically forms circular marks with serrated edges.
- Blood falling from a moving object will hit a surface at an angle, forming a spatter with smaller spots showing the direction of the movement.
- Spines can help to make a rough estimate of the height a spatter was dropped from.
- The shape of the blood spatters can help estimate the steepness from which the blood fell.
- Castoffs are droplets of blood released behind a moving weapon.

Fingerprints
Fingerprints are the marks left behind when someone touches an object with their finger. They can be collected by dusting (if on non-porous surfaces) or on absorbent surfaces they can be collected using iodine.

There are three main patterns: arches, whorls and loops.
65%- loops
30%- whorls
5%- arches

Patent Prints
Prints that are clearly visible such as those made by hands covered in blood, soot or dirt.

Latent Prints
Patterns made by oil soot and dirt on the ridges of fingertips. They are not clearly visible and must be developed in some way so that they can be seen.

Exemplar Prints
(also known as exclusion prints)
Deliberately collected from a suspect to be compared to prints from the crime scene.

Handwriting Analysis
Handwriting analysis can be useful in cases involving cheques, letters, wills and suicide notes. Comparisons are made by looking at twelve different factors including spaces, dotting & crossing, and fancy loops & swirls.

Dental Records
Teeth can change with time meaning that dental records aren't always helpful. However, teeth are resistant to fire so records can be used to help identify a body.

Bullets and Ballistics
Bullet Matching
Each gun has a distinct pattern (rifling or striations), meaning that scratch marks on a bullet are like 'fingerprint' from the gun that fired it. If a gun is suspected of being used in a crime, another bullet can be fired from it and the scratch marks can be compared. This is known as test firing and bullet matching.

Gunshot Residue
Gunpowder in bullets usually contains traces of barium, lead and antimony. If someone is arrested for gun crimes their hands will be swabbed and analysed using atomic absorption spectrometry. If traces of these elements are found, they generally indicate that someone has been firing a gun.

Test Firing
Test firing is used when a bullet found at a crime scene needs to be matched to a gun. Guns suspected of being used will have a test bullet fired and then the scratches on the bullet will be compared.

Entry and Exit Wounds
Entry holes are relatively neat and clean while exit wounds are far more ragged (and larger).

Autopsy
An autopsy is a medical examination performed on a body that has died under mysterious circumstances to determine time and cause of death. Forensic autopsies are performed by forensic pathologists while clinical autopsies are performed in hospitals by pathologists.

The procedure for an autopsy is as follows:
- the seal of the body bag is broken and the person is photographed
- evidence is collected off of external surfaces of the body
- any wounds are examined and the body is cleaned up
- the body is weighed and measured and then a general description of the body is recorded
- a deep y-shaped incision is made in the chest
- skin, muscle and soft tissue are peeled back using a scalpal
- the organs are examined

Causes of Death
Natural
A natural disease process such as leukemia or cancer.

Accident
Death caused by a fall or car crash that is not homicide or suicide.

Suicide
Self-inflicted death.

Homicide
Unnatural death caused by another person.

Undetermined
The cause of death cannot be reasonably determined.

Time of Death
Time of Death Certainty Principle
If you know with certainty when the person was last known to be alive and you know with certainty when they were found dead then you know with 100% certainty that they died within that interval.

Ways of Estimating Time of Death
Body Temperature: A body's temperature falls around 1.5oC each hour after the person dies.
Rigor Mortis: Muscle fibres lock solid. This takes full effect after 6-8 hours and lasts for 20-30.
Lividity: Blood settles by gravity to the lowest parts of the body causing discolouration which becomes permanent after 3-5 days.
Cloudy Vitreous Humour: The corneas become cloudy.
Decay: The body turns green after two to three days.
Insect Evidence: Tells forensic scientists how long the body has been outside.

Identification
- Remains and scars of illness, injury and operation.
- Unusual tatoos, birthmarks and piercings.
- Shape and structure of hair.
- Skeleton. (information about age and sex)
- Size of bones.
- Facial reconstruction.
- Dental remains and records.

caffinatedloz

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Re: Forensics: Summary Notes
« Reply #1 on: December 11, 2019, 07:50:20 am »
+3
Forensic Psychology
Dangerousness
The liklihood of a person commiting a serious act of violence with little provokation.

Criminal Profiling
A technique used to assist in the identification and apprehension of a likely criminal offenders for a crime or series of crimes.

A criminal profile is an overall portrait of a likely offender, including:
-psychological characteristics
-physiological characteristics
-employment status
-socioeconomic status
-marital status
-clothing preference
-their type of vehicle

Mental Disorders and the Law
People cannot be held legally responsible for a crime unless they had the intention to commit it, known as 'mens rea'.

It can be argued that a person is not legally responsible due to a lack of 'mens rea' because of automatism, their age or diminished responsibility.

Diminished responsibility is an unbalanced mental state that makes a person less answerable for their crimes in relation to a murder case.

Schizophrenia
Positive & Negative Symptoms
Positive symptoms are things that are added to a person's experience of the world like hallucination snad delusions.

Negative symptoms are things taken away from a person's experience of the world. Examples include word salad, apathy, lacking a full range of emotions and difficulty socialising.

Crime & Schizophrenia
One in ten men and one in five women are diagnosed with a psychiatric disorder in prison.

It has been shown that there is a link between people with uncontrolled
(mismanaged) psychotic disorders and crimes.

Prevalence
Approximately 1% of the population has schizophrenia.

Treatment
-Medication
-Talk Therapy
-Hospitalisation
-Electroconvulsive Therapy

Antisocial Personality Disorder
Symptoms & Features
-Guiltless
-Lacking Emphathy
-Selfish
-Manipulative

Treatment
Although there is no treatment, there are some options that can help to manage the symptoms of the condition.

-Talk Therapy
-Anger Management
-Medication

Prevalence
In general society, 4% of men and 1% of women have the condition while between 40 and 70% of the prison population has it.

Stalking
Stalking is a person's persistent attempts to force unwanted communication or contact on a person that causes fear and distress.

The types of stalkers are:
-Rejected
-Resentful
-Intimacy
-Incompetent
-Predatory
-Delusional

Stalking is a crime because it has a profound psychological and physical impact on a victim.

Lies and the Polygraph
The polygraph is performed by:
-establishing an individual's base level of physical arousal when calm
-asking further control questions to elicit a slight response
-asking relevant questions throughout

Polygraph machines measure physiological arousal by measuring heart rate, blood pressure and sweating.

The polygraph can be cheated by people increasing their baseline arousal so that they do not appear to be lying when, in fact, they are.

Psychology in Prison
Institutionalisation is the process in which inmates are shaped and transformed by the institutional environments in which they lived.

When leaving, prisoners may struggle to trust others, think independently, avoid reoffending and develop strong relationships.

Psychologists in prison can work to develop programs and strategies related to the needs of criminals and reducing reoffending as well as carrying out specialised assessments and providing basic mental healthcare.

Memory
Hypnosis
People in a hypnotic state are very relaxed and highly open to suggestion. Hypnosis can be used in healthcare to help people stop smoking, lose weight or manage pain and deal with specific phobias. Forensic hypnosis can be used to help people give detailed accounts of a crime they have witnessed. Although hypnosis can be useful in helping witnesses recall their experience, it may also leave people susceptible to leading questions and contaminate their memory.

How Does Memory Work
sensory input -> sensory memory -> short term memory -> long term memory

Encoding: The information is ocnverted for storage.
Storage: The information is retained in memory.
Retrieval: The information can be recovered for later use.

Memory is like a puzzle and as we recall events, we must reconstruct the memory. Gaps are filled with assumptions that can be affected by questioning techniques.

Eyewitness Testimony
Loftus and Palmer conducted two experiments to test the effect of leading questions on memory and look at the way that false memories may be created.

Weapons focus, the cross-race effect and leading questions can all alter the way that memories are reconstructed.

Ways of Improving Memory
Memory can be improved by providing aids or clues such as photos, identity line-ups or crime scene visits as well as asking the witness to start at various points of their testimony or retell things in the reverse order.