Forensic Science:A Brief Introduction to the Disciplines

November 2015

Jane Austin

(Any errors in this presentation are all mine)

Today’s Session

• Historical Context

• Overview of Forensic

Science Disciplines

• How they are used in

crime investigations

Historical Context

• Forensic Science dates back to 12thC… gathered

momentum in 17thC

• The word forensic comes from the Latin, forēnsis, meaning

"of or before the forum."

• Term originates from Roman times (a criminal charge was

presented to a group of public individuals in the forum).

• Autopsy - from Greek, from autoptēs ‘eyewitness’, from

autos ‘self’ + optos ‘seen’ – to see for oneself

• Recently, made popular in books and Tv series such as CSI,

NCIS, Silent Witness

UK

Sir Bernard Spilsbury

1877-1944

• Studied at St Mary’s Hospital,

Paddington in 1899.

• Specialised in emerging science of

FORENSIC PATHOLOGY

• First and most famous case was

the trial of Hawley Harvey Crippen

(“Dr Crippen”)

Dr Crippen

• Provided forensic evidence that the

victim found in Crippen's house was

Mrs Cora Crippen

• Based on a scar on a small piece of

skin from the remains.

• But…….

• Spilbury's authoritarian approach and his

unnerving self-belief gave rise to criticism

among judiciary

• Recent research has shown that some of his

conclusions led to miscarriages of justice

• That said, in 2008, files containing Spilsbury’s

detailed notes on deaths (from 1905-1932) went

to Sotheby's and were acquired by the

Wellcome Library, London.

Spilsbury’s Cases

Wellcome Trust

• Biomedical research charity, established 1936, to fund biomedical research, support public understanding of science, and improve human and animal health.

• UK’s largest provider of non-governmental funding for scientific research and one of the largest providers in the world.

• In medical research, it is world's second-largest private funder after Bill & Melinda Gates Foundation (ref. FT)

Well worth a visit!

Wellcome Trust

USA - Frances Glessner Lee (1878-1962)

• In 1936 inherited the family fortune. Developed a passion

for forensics, inspired by her brother’s friend, Magrath,

who was Boston’s medical examiner

• Wanted to reform the country’s legal medicine system.

• Donated money to Harvard to create a Chair for Legal

Medicine and GB Magrath Library of Legal Medicine

• Established the first US forensic pathology program

• Most remembered for her dioramas of crime scenes

• “The Nutshell Studies of Unexplained Death"

Dioramas of Crime Scenes

Dioramas of Crime Scenes

Forensic Disciplines

• Biology, Chemistry, Physics

• Anthropology

• Botany and Ecology

• Blood Pattern Analysis

• Dentistry

• Digital

• DNA Profiling

• Engineering

• Entomology

• Pathology

• Psychology

• And many more…..

Forensic Botany

Forensic Botany

Scientific study of plants, or the application of plant sciences to criminal investigations.

Incorporates a number of sub-disciplines:

• palynology (pollens)

• dendrochronology (tree rings)

• limnology (aquatic environments)

• systematics (the classification of plants)

• ecology (ecosystems), and

• molecular biology.

Forensic Botany

• Forensic botanists examine plant matter to

determine their species and origin.

• Suspects may leave behind plant parts, spores or

seeds adhered to their clothing.

• Some species found only in limited areas…. their

presence at the crime scene may indicate where

suspects have been or where they live/work.

• Forensic botanists also can be essential in locating

clandestine gardens or greenhouses used to

cultivate such illegal plants as marijuana.

Pollen

• Powder-like, abundant and easily

transported. Pollen grains are often

found on clothes, hair or skin.

• Can connect a suspect to a victim or

crime scene….

• If investigators find a rare plant type

near a murder victim, the presence of

its pollen on suspect could place them

at the scene. Images:

Rob Kesseler Madeline Harley

Pollen

• Even for common plants, each

environment has its own unique

combination of pollens; this 'signature'

can link an individual or object to a

location.

• Pollen signatures may also indicate that

a body has been moved or suggest the

type of area where the original crime

took place.Images:

Rob Kesseler Madeline Harley

Botany and

hidden graves

• When soil disturbed, certain plants quickly invade the fresh

surface.

• Other species follow in succession until the area recovers.

• But the new composition and distribution is never identical

to original plant community.

• Also, a buried body may chemically change the soil, and

may promote or inhibit growth - area will be different from

its surroundings.

• These differences may be visible for decades.

Botany and the

time since death

• Diatoms can be used to diagnose death by

drowning in freshwater.

• Botanists identify number and species of

diatoms present in lungs and other tissues,

correlate them with flora from location of body.

• Diatoms vary seasonally, and this can also help

in approximating time since death.

• Unique ‘Signature' of an aquatic habitat can

match a body to a given location

Botany and time since death

• Trees and roots are also useful for determining elapsed

time since death

• Woody plants and trees grow in annual cycles and the

growth rings can provide clues to the timing of an event,

sometimes centuries later.

Particularly accurate if roots grow

through clothing or bone. Even partial

damage to root growth can suggest the

period since the burial occurred.

Forensic Dentistry

Forensic Dentistry

Main areas of practice:

• Identification of human remains

• Identification in mass fatalities

• Assessment of bite mark injuries

• Assessment of cases of abuse (such as child,

spouse or abuse of the elderly)

• Age estimation, race, occupation, socio-

economic status

Blood Pattern Analysis (BPA)

Blood Pattern

Analysis

• The interpretation of bloodstains at a crime scene

in order to recreate the actions that caused the

bloodshed.

• Analyse size, shape, distribution and location of

bloodstains

• Form opinions about what did or did not happen.

Typical scene

Blood Pattern

Analysis

• Chemical considerations - red to brown as

oxy-haemoglobin changes to

methaemaglobin and haemichrome

• Physical considerations - fluid to solid,

effects of gravity, viscosity, surface tension

• Flight characteristics - angle of impact,

area of origin

Bloodstain Pattern

Analysis

Digital Forensics

Digital Forensics

• Digital Forensics is study of information stored or

transmitted in digital form that may be used in trial

• Before accepting digital evidence, a court

determines if evidence is relevant, authentic and

whether copy or original is acceptable.

• Need assurances regarding chain of custody

Digital Evidence

Use of digital evidence increased in last few

decades…. Many high profile cases in the press

Courts have allowed the use of range of evidence:

• Emails, digital photos, video and audio files

• Instant messaging histories

• ATM transaction Logs

• Accounting programs and spreadsheets

• WP documents

• Internet Histories, Database records

• Contents of computer memories

• GPS tracking/Mobile Records

• Logs for hotel electronic door locks

Defending a Digital Case

Common lines of defence are that:

• Trojan or 'pop-up' was responsible for presence of any illegal material on the defendant's computer.

• Such material was unsolicited and was 'pushed' to them via MSN, a peer to peer application such as Kazaa or email.

• It was one-time idle curiosity….

Prosecuting a Digital Case

Such “explanations” can be countered by proving that the

defendant had sought such material by:

• signing up to a service using a credit card

• searching within a peer-to-peer application

• entering keywords in an internet search engine

• sheer quantities of material and periods of exposure

For digital evidence to be admissible, a clear “chain of

custody” required, detailing who had access to digital

device & when, contemporaneous notes of all actions

taken, particularly in relation to the technical processes.

DNA Profiling

DNA Profiling

Developed from two independent breakthroughs in

molecular biology:

• In USA, the polymerase chain reaction (PCR) was

invented by Kary Mullis

• In UK, DNA fingerprinting was being discovered by

Professor Sir Alec Jeffreys at the University of

Leicester.

• Multi-locus probing (MLP) technique results in probes

binding to multiple DNA fragments, giving rise to

traditional 'bar-code' pattern.

DNA Short Tandem Repeats

• DNA profiling involves the testing of highly variable

regions of a person’s DNA that contain short repeating

sequences called STRs (short tandem repeats).

• Because we inherit DNA from both parents, DNA

profiles can be used to confirm if people are closely

related eg paternity, siblings

• STR very sensitive technique, requires only a small

quantity of DNA eg blood, semen, skin, saliva,

mucus, perspiration and the roots of hair

First Conviction using

DNA Profiling

Professor Jeffreys used DNA techniques to link semen

stain samples, collected from two rapes/murders that

occurred 3yrs apart (1983 & 1986), in a small

Leicestershire village.

• Semen was type found in only 10% of men, and was

from someone with Type A blood group.

• As a result, first mass DNA profile screening in the

world was undertaken in Leicester

• Blood and saliva samples from 4,000 men with no

alibi who lived in the local villages

But still no DNA match was found…….

• In August 1987, a woman overheard a colleague boasting

that he had given a sample for a friend, Colin Pitchfork.

• Police arrested Pitchfork in September 1987, and scientists

found that his DNA profile matched that of the murderer.

First Conviction…

In this first case, DNA profiling and screening was able to :

• Link the two crimes, several years apart

• Secure the conviction of the perpetrator

• Exonerate an innocent man.

Only one-in-a-billion chance that profiles are from

two different people, unless they are identical twins.

Forensic Entomology

Forensic Entomology

Involves the study of arthropods, including insects,

arachnids, centipedes, millipedes, and crustaceans in

criminal or legal cases … murder, suicide, rape,

physical abuse and contraband trafficking

Forensic

Entomology

• In murder investigations, the focus is on:

• which eggs (eg types of insects) are present

• their location on the body, and

• in what order they appear.

• This is helpful in determining Postmortem Interval

(PMI) and Location of death.

Hence, their presence

together with other

evidence can also point

to times and locations

where other events

may have occurred.

Many insects exhibit:

Endemism (occur only in certain places)

Phenology (active only in certain season, or time of day).

Forensic Entomology

Blow Flies

• Blow flies are first insects to come in contact with dead

body… great forensic importance

• Reputedly, they have the ability to “smell death” from 10

miles away.

• Blow flies (Calliphoridae) often metallic in appearance,

10 - 14 mm in length. Includes blue bottles; 1200 species

• Hatching from egg to first larval stage takes from 8hrs to

one day. Found in temperate to tropical areas….larvae

thrive and pupate in loose, damp litter.

Photo by:

L. West/Bruce Coleman Inc

Blowflies and Decay

• Duration of decay process depends on climatic

conditions & yearly temperature changes

• Corpses in summer and rainy season decay at

much faster rate than those in winter and spring.

• Lower temperatures slow down the development

of the larvae (maggots).

• Higher temperature of the corpse due to maggot

activity (core maggot mass) itself also speeds up

decay.

Forensic Psychology

• Forensic psychology is the intersection between psychology and the justice system.

• Includes clinical, social, organisational or any other branch of psychology….

• Important aspects of forensic psychologist’s work includes the ability to:

• testify in court as an EXPERT WITNESS

• discuss cases that involve issues with the brain or brain damage. They may also deal with issues of whether a person is legally competent to stand trial.

• assess the state of mind of the defendant at the time of the offence, and to provide an evaluation of the defendant's sanity or insanity (which relates to criminal responsibility) at the time of the offence.

• provide sentencing and treatment recommendations, or any other information the judge requests, such as information regarding mitigating factors, assessment of future risk and evaluation of witness credibility.

And finally…

Body Farms

Body farms

• A body farm is a research facility where

decomposition can be studied in a variety of

settings.

• Aim - to gain a better understanding of the

decomposition process, to develop techniques for

extracting information (such as the timing and

circumstances of death) from human remains

• Six such facilities exist in the United States.

• Largest facility is operated by Texas State

University (7 acres).

Thank you for listening