CFS Bulletin
Issue 3 April 2012
w: www.ucl.ac.uk/forensic-sciences
e: jdi-forensic-sciences@ucl.ac.uk
@UCLForensicSci
in this issue:
• Imperfect Prints: how fingerprint evidence is being scrutinised by the forensic science
world
• Professor Norman Fenton visits the Centre for the Forensic
Sciences to talk about the
Bayes and Law Network
• We profile a current forensic
science PhD student taking
part in the SECReT programme
• News and events from the
Centre for the Forensic Sciences and elsewhere including
the next National Environmental Crime Conference on
17th April
• Bursaries are available for the
new MSc in Crime & Forensic
Science
Imperfect Prints:
the trouble with
fingerprints
For over a century, fingerprints
(known as marks or latent prints)
found at the scene of a crime
have been used to help identify
criminals. Fingerprint experts
give their opinion on whether a
particular set of marks match a
set of fingerprints on file, and this
opinion is necessarily subjective.
Indeed, recent research carried
out in the United States by the
National Institute of Standards
and Technology (NIST) and the
Department of Justice’s National
Institute of Justice (NIJ) investigates the effects of human factors
on forensic fingerprint analysis
and concludes that work is needed to reduce human error. Their
report – Latent Print Examination
and Human Factors: Improving
the Practice through a Systems
Approach1 – makes recommendations relating to a range of issues
including laboratory design,
equipment, training and communication.
A factor that has a great influence on how fingerprints are used
1: http://www.nist.gov/manuscript-publicationsearch.cfm?pub_id=910745
in criminal cases is this: fingerprint evidence is not permitted
in court at all unless fingerprint
experts state that they are 100%
certain that a mark has been left
by a particular suspect. In his
recent article for Significance, the
magazine of the Royal Statistical
Society and the American Statistical Association, Professor Cedric
Neumann of Penn State University draws attention to what he sees
as a ludicrous state of affairs:
“Strangely, DNA experts are
required to give probabilities for
their evidence of matching; fingerprint experts are forbidden to.
This bizarre situation ought to be
ended, in the interests of justice as
well as common sense.” 2
Professor Neumann goes on
to suggest that what is needed,
rather than the present system
of a “pretended certainty” one
way or the other, is a way to give
quantified, numerical figures to
the probability of a match. In
other words, an empirical method
is required to enable a more
objective and probability-based
approach. A fingerprint is a pat2: Neumann, C. “Fingerprints at the crime-scene:
Statistically certain, or probable?” in Significance, Volume 9, Issue 1 (February 2012) DOI:
10.1111/j.1740-9713.2012.00539.x
tern: too complex as a whole for
mathematics or even fingerprint
experts to analyse. Certain parts
of the print – arches, loops and
whorls – are sufficient to be used
for recognition and classification.
In criminal cases finer detail is
required and experts use points
of detail called minutiae, of which
there can be dozens in a whole
fingerprint but very few in marks
recovered from crime scenes.
He proposes a new method,
devised by his team at Penn State
University, that derives numbers
from these minutiae; arguing
that this gives a more objective
statistical rationale compared to
the reasoning that currently leads
experts from minutiae to identification: “…essentially a psychological one that cannot be rationalized and rendered explicit.”
Their new method was tested for
both positive and negative errors
using marks or traces from the
scenes of 364 crimes committed
in Wales, UK compared to fingerprints obtained from the national
fingerprint database in the US.
The results were promising, and
he hopes that in the future there
will be “an evolution towards a
framework that is similar to that
which underpins DNA evidence.”
Battles over this new method are
expected, but he argues that models such as this one are “a powerful platform for change.”
It remains to be seen how this article and the report published by
the NIST and NIJ will influence
the use of fingerprint evidence in
the US and elsewhere. But many
working in the field will see these
recommendations and methods as positive developments in
forensic science, hopefully leading
to more robust evidence in court
and consequently fewer miscarriages of justice in future.
The Bayes and Law
Network
We were very pleased to have a
visit from Professor Norman Fenton - Professor of Risk Information Management at Queen Mary,
University of London - in March.
He gave a seminar to academics
and students from UCL and the
University of Oxford on his recent
venture: Bayes and the Law
Network - Transforming Legal
Reasoning through Effective Use
of Probability and Bayes. This
network is intended to explore
the role of Bayesian reasoning in
criminal justice, and has attracted
senior academics in the fields of
statistics, law, computer science
and forensic science, as well as
civil servants across Europe.
The use of Bayesian networks in
legal settings has been the subject
of a recent ruling in the Court of
Appeal: “...no attempt can realistically be made in the generality of
cases to use a formula to calculate
the probabilities...it is quite clear
that outside the field of DNA (and
possibly other areas where there
is a firm statistical base) this court
has made it clear that Bayes theorem and likelihood ratios should
not be used.”1
Professor Fenton believes that as a
result of this ruling, many lawyers are playing safe and avoiding
the use of Bayesian tools such
as likelihood ratios and probabilities, preferring to stick to
verbal equivalents. He argued
that Bayesian networks can be
used with many different types of
evidence, and that lawyers, judges
1: R v T, 2010
and juries should be able to
understand Bayes theorem in its
simplest form. In reality of course,
things are rarely simple, but the
use of Bayesian networks can help
to clarify probabilities nonetheless.
In answer to the argument that
their complexity means formulae
should not be used in court, due
to the fact that jurors etc. cannot
understand them, he used the
analogy of a complicated sum,
solved with the use of a calculator. No-one would suggest that
the answer to the sum shouldn’t
be relevant because they do not
understand how the calculator
itself works!
In conclusion, Professor Fenton
suggested that “the only rational
way to evaluate probabalistic
evidence is being avoided because
of basic misunderstandings.” The
challenge for his network is to
develop methods to make building legal Bayesian network arguments easier for lawyers. It is a
significant challenge, but one that
academics, lawyers and judges
alike would like to see overcome.
To find out more about Professor
Fenton’s work, visit his website and
his blog on probability and the law:
w: https://sites.google.com/site/bayeslegal/
w: http://probabilityandlaw.blogspot.com/
e: norman@eecs.qmul.ac.uk
Cutting edge research
A main aim of the CFS is to bring
academics and practitioners
together with students working
within the field of forensic science, to facilitate cutting edge
research. One such student is
Nadia Abdul-Karim, enrolled on
the SECReT doctoral training
programme since 2010.
Having graduated from Staffordshire University with a BSc
in Forensic Science, Nadia felt
that the opportunities offered by
the 4-year SECReT programme
would enable her to engage fully
with industry, as well as other researchers. Her PhD - Investigating
Patterns in the Spatial Distribution of Post-Blast Explosive Residues - aims to address the current
lack of any scientifically valid
method for locating explosive
residues at crime scenes.
Currently, crime scene investigators collecting evidence at the
scene of an explosion will focus
on collecting it from areas with
obvious signs of damage. However, Nadia has found during the
course of her research that these
areas do not always yield explosive residue. Given the importance of collecting any residue as
soon as possible, it is vital that
investigators know where to look
for it.
For her MRes project, Nadia
carried out several test explosions at Cranfield University’s
Defence Academy of the United
Kingdom, based in Shrivenham,
Oxfordshire. Various sampling
sites within range of the explosions were tested for residue.
More residue was found closer to
the centre of the explosion, and
more residue was found when
the height of the detonation was
increased. An article on this research has recently been accepted
for publication by the Journal of
the Forensic Sciences.
For her PhD, she is extending
the research to examine confined detonations (e.g. explosives
contained in small and large
rucksacks and various metal
encasings), the use of various
explosives, and multiple sampling
media. Results gained from chemical analysis, blast pressure measurements and high speed imaging
technology will be compared in
order to enhance understanding
of the deposition of residues after
a detonation.
All students enrolled on the
SECReT programme are required
to show that their research has an
impact on industry, and to this
end they aim to collaborate with
and gain sponsorship from different organisations within their
chosen field. Nadia has successfully forged collaborations with
Cranfield University, CAST (the
Centre for Applied Science and
Technology at the Home Office),
the Forensics Explosives Laboratory at DSTL and the Metropolitan Police Service.
The long term aim of this research
is to help crime scene investigators retrieve and analyse explosive residue from scenes that by
their very nature are chaotic and
difficult to examine. By working
closely with practitioners in the
field and organisations with the
equipment and expertise to help,
Nadia is well-placed to achieve
this goal.
To see updates on Nadia’s research,
visit the SECReT website.
w: http://www.ucl.ac.uk/secret/homepage/
e: nadia.abdul-karim.10@ucl.ac.uk
w: http://www.cranfield.ac.uk/
w: http://www.homeoffice.gov.uk/scienceresearch/cast/
w: https://www.dstl.gov.uk/
w: http://content.met.police.uk/Home
What is SECReT?
UCL SECReT is a £17m international centre for PhD training in
security and crime science, the
first centre of its kind in Europe.
It offers a comprehensive integrated PhD programme for students
wishing to pursue multidisciplinary security or crime-related
research degrees.
Students from a range of scientific
backgrounds pursue research in
crime or security domains across
the engineering and social sciences. They can enter the programme
through a number of funding
routes (self-funded, industry
sponsorship, scholarships).
In 2012 there are 11 EPSRC scholarships available and the deadline
is fast approaching, so interested
applicants should visit the website: www.ucl.ac.uk/secret/homepage/
Stay in touch
News and events
National Environmental Crime
Conference
Tuesday 17th April 2012
Wellcome Collection
Conference Centre, London
From the illegal extraction and
trade of natural resources to
industrial pollution and illegal
transport of hazardous waste, environmental crimes threaten national economies, human health
and the global environment.
Following on from the first two
highly successful National Environmental Crime events, the
NECC 2012 will bring together
scientific communities, practitioners and the technology
industry to reflect on the role of
emerging technologies in the fight
against environmental crime.
Attendance at this conference is
free and you can register here:
http://www.eventbrite.com/event/3145364871
CFS Research Seminar
Wednesday 9th May 2012
UCL
We look forward to welcoming
Mr Denis Edgar-Nevill (Canterbury Christchurch University) to
talk about the increasingly important field of computer forensics.
Advances in technology mean
that criminal investigations must
keep ahead of the game, and
university-led research is key.
Places at the seminar are limited,
so if you would like to attend
please email us for details.
External events
To keep up-to-date with news
from the CFS, events we are running and external news in the
forensic science field, why not
visit our website and follow our
newsfeed on Twitter?
w: www.ucl.ac.uk/forensic-sciences
@UCLForensicSci
FSS Conference
28th April 2012
York
e: jdi-forensic-sciences@ucl.ac.uk
Are you open to Suggestion? The
Role of Subjectivity and Influence
in Evaluation
Bursaries available for
new MSc
The Forensic Science Society will
be holding a one-day conference
in April to look at the role of Cognitive Bias in Forensic Science.
w: www.forensic-science-society.org.uk/Events/2012/
6th FORSTAT Workshop
5th-8thJune 2012
Edinburgh
Forensic Evidence Evaluation:
Problems and Applications
The intention of the series of
FORSTAT workshops is to train
forensic scientists in the statistical
evaluation of evidence. The level
of the presentations is aimed at
those who are forensic experts but
may be beginners in statistics.
Registration costs £225 and the
deadline for registering is 1st May
2012.
The new MSc in Crime &
Forensic Science is proving very
popular since applications opened
on 1st January 2012.
The CFS is providing two bursaries, which can be applied for at
the same time as applying for the
MSc programme. See our website
for further details:
www.ucl.ac.uk/forensic-sciences/teaching
The deadline for bursary applications is 30th April, so don’t delay
if you want to be considered.
Awards will be made on the basis
of academic merit. Applications
for the programme itself are open
until summer 2012 for the 20122013 academic session.
cfs bulletin
APRIL 2012
Editor: Kirstie Hampson
w: http://ies.krakow.pl/conferences/forstat2012/
The next issue of the
CFS Bulletin will come
out in July 2012.