LCV
Leucocrystal Violet. Reagent used to detect / enhance bloody friction ridge detail by either
fluorescent or nonfluorescent staining.
SWGFAST, Glossary – Consolidated 09-09-03 ver. 1.0
Langenburg, Glenn
Glenn Langenburg earned a BS in Forensic Science from Michigan State University in 1993 and
a MS in Analytical Chemistry in 1999 from the University of Minnesota. He earned his PhD in
2012 from the University of Lausanne, Switzerland researching the statistical analysis of
fingerprint comparison methodology. In addition to working as a forensic scientist, Dr.
Langenburg has been an adjunct professor at Hamline University and Metropolitan State
University in Minnesota. He also served as a member of SWGFAST until it was dissolved in
2013.
Langerhans Cells
Cells in the stratum spinosum layer of the epidermis designed to process foreign antibodies to the
immune system.
Langill Decision (2007)
See State of New Hampshire v. Richard Langill.
Laser
Light Amplification by Stimulated Emission of Radiation. A device that produces a coherent
wavelength(s) of light. See FLS.
SWGFAST, Glossary – Consolidated 09-09-03 ver. 1.0
First used for viewing latent prints by a team of Canadian researchers in 1976. These
researchers were E. Roland Menzel of Texas Tech University, Brian E. Dalrymple of the Ontario
Provincial Police, and J.M. Duff of the Xerox Research Centre of Canada.
J. Forensic Sci. 22, (1), 106 (1977).
A special lens is used to expand the laser beam to the entire viewing area.
The first testimony in the United States regarding this method of visualization was in 1981 in
Sierra Vista, Arizona by Ed German.
Latent Print
A transferred impression of friction ridge detail that is not readily visible to the naked eye; A
generic term used for a friction ridge impression that was not intentionally recorded.
A fingerprint that is not apparent to the eye but can be made sufficiently visible, as by dusting or
fuming, for use in identification.
The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2000 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved
http://dictionary.reference.com/search?q=latent&r=3 02-27-03
1. Transferred impression of friction ridge detail not readily visible.
2. Generic term used for unintentionally deposited friction ridge detail.
SWGFAST, Standard Terminology of Friction Ridge Examination 3-23-11 ver. 3.0
Latent Print Age Determination
The length of time a latent print can remain on an item is dependent on the latent print
composition, the environment factors, and the substrate. A latent print made up of perspiration
may evaporate quickly while a latent print composed of fatty material may remain on an item for
years. The age of a latent print cannot be determined by visualizing the latent print.
Latent Print Composition
A latent print is composed of the material transferred from the friction skin onto an item. The
composition can be eccrine sweat, sebaceous sweat, blood, oil, paint, lotion, etc. The
composition of a latent print can only be determined by chemical analysis and should not be
presumed to be perspiration.
Latent Print Examiner
See Friction Ridge Examiner.
Latent Print Recovery Conditions
Whether or not a latent is recovered is dependent on:
The surface (substrate):
a) Its physical composition,
b) Its texture,
c) Condition,
d) and cleanliness.
The person touching the item:
a) The condition of their ridges (which could be affected by medical condition or
occupation),
b) how much they sweat (which is dependent on age, diet, temperature, emotional state,
medical condition and the recent amount of physical exertion),
c) And the pressure they apply.
Whether or not there is a transferable substance on the friction skin other than sweat.
Post transfer conditions:
a) The environment (heat or rain will deteriorate a latent),
b) How it’s handled (handling and packaging may destroy a latent)
c) and the developing medium.
Latzina, Dr. Francisco
A fingerprint pioneer that is credited with influencing Vucetich to change the name of his
classification system from Icnofalangometria to Dactiloscopy.
Law of ACE’s
“… a process of Analysis, Comparison, and Evaluation (Huber’s law of ACE’s).” Chapter 5,
Handwriting Identification: Facts and Fundamentals, Roy A. Huber and A.M. Headrick 1999 CRC
Press
Law of Biological Uniqueness
The Scientific Law that states that all items in nature are unique.
Laws
Generalizations about what has happened, from which we can generalize about what we expect
to happen. They pertain to observational data. The ability of the ancients to predict eclipses had
nothing to do with whether they knew just how they happened; they had a law but not a theory.
http://www.madsci.org/posts/archives/oct99/940942724.Sh.r.html 02-27-03
States an observation without any attempt to explain it (law of gravity).
Leadbetter, Martin FFS, RFP, Bachelor of Arts + Honours
Martin Leadbetter was employed within the Fingerprint Branch at New Scotland Yard from
1966/72. During this period he was also responsible for attending crime scenes in Central
London as a Divisional Fingerprint Officer. Having qualified as a Fingerprint Expert in 1972, he
transferred to the Gloucestershire Constabulary where he remained employed for just over two
years, after which he took up the post of Deputy Head of the Fingerprint Bureau for Hertfordshire
Constabulary, just north of London.
In 1988 he was seconded to the Home Office as part of the team investigating implementation of
a national AFIS for England and Wales. This secondment lasted until 1991 and during this time
he assisted in the writing of the Detailed Operation Requirement for a national AFIS and made
several visits with the bench-marking team to the USA and France where systems produced by
Printrak, NEC, Morpho Systèmes (now Sagem) and ISS were all tested.
From January 1991/August 1995 he was employed by Sagem SA as Fingerprint Expert and
Consultant. During this period he visited the police departments of more than thirty countries
worldwide, including two visits to Siberia, South American countries, South Africa, numerous
visits to the USA, Russia and most European countries.
In September 1995 he took up his present post as Head of the Fingerprint Bureau for
Cambridgeshire Constabulary, based in the East Anglian region of the UK.
He has been a member of IAI since 1978, a Distinguished Member since 1988 and achieved Life
Membership in 2003. He is a Founder, Fellow and Life Member of The Fingerprint Society and
was its first Secretary and Assistant Editor of the Society’s journal, Fingerprint Whorld for just on
fifteen years. Today, Mr. Leadbetter is a serving member of The Fingerprint Society Committee.
Recently, he has acted in a consultative position in Bosnia, assisting the European Union Police
to implement a national AFIS for that country. He has addressed several conferences, both at
home and abroad, in particular at the Humboldt University, East Berlin, Surgut, Siberia and most
recently, in October 2004 at the Centenary Conference in Budapest, which celebrated the first
hundred years of the fingerprint system in Hungary.
At home he is now very active holding several important national posts. He is a member of the
National Fingerprint Board of England and Wales, Chairman of the Bureau Practitioners’ SubGroup and a member of the Standards Working Group. Until recently he chaired the Third Level
Detail Sub-Group, which had been instigated by the Association of Chief Police Officers to
investigate the potential use of so-called ‘third level detail’ within the identification process. He
also sits on the IAI’s International Committee and is a member of the Journal of Forensic
Identification’s Editorial Board.
He is a Registered Forensic Practitioner with the Council for the registration of Forensic
Practitioners and Member of the British Academy of Forensic Sciences and holds the degree of
Bachelor of Arts with Honours.
Throughout his long career within the fingerprint discipline he has been a constant contributor to
forensic and scientific journals. He strongly holds the view that fingerprint identification is not a
science, but a technique that requires considerable skill, but is prepared to compromise and
accept that it has a scientific, albeit a rather nebulous ‘scientific’ basis.
In his spare time Martin Leadbetter enjoys gourmet cooking, wine and is a composer having
written three symphonies, numerous works for chamber and instrumental ensembles, more than
fifty songs, and works for choir, band and orchestra. He is also a Member of the Corporation of
the Royal Albert Hall, London. As an author he has just completed his first full-length novel, Deep
and Crisp and Evil, which gives an uncompromising insight into the working of the modern police
service and forensic discipline.
11-24-2004
Martin Leadbetter retired from the Cambridgeshire Constabulary on Aug. 12, 2005.
Leuco Rhodamine 6G
A reagent that reacts with the heme moiety of the hemoglobin of red cells in blood to visualize
friction ridge detail left in blood. The sulfosalicylic acid in this solution fixes the blood so no
pretreatment is necessary.
Luo Yapping and Wang Yue. Journal of Forensic Identification Vol. 54, No. 5, 2004
Leucocrystal Violet
A colorless or reduced form of gentian violet (per the FBI) used to stain blood residue (through
oxidation) on both porous and nonporous items. Aka LCV.
Leucomalachite Green
Reagent used to detect / enhance bloody friction ridge detail.
SWGFAST, Glossary – Consolidated 09-09-03 ver. 1.0
LeuR6G
See Leuco rhodamine 6G.
Level 1 detail
General overall pattern shape, i.e., circular, looping, arching, or straight.
Quantitative-Qualitative Friction Ridge Analysis, David R. Ashbaugh 1999 CRC Press
In Nov. 2004, the Third Level Detail working group (from the Standards Sub-Group of the
National Fingerprint Board of England and Wales) determined that it was not necessary to
subdivide the features used in friction ridge identifications. In England and Wales these terms are
no longer recognized and it has been established that they should not be used. See Features.
Friction ridge flow, pattern type, and general morphological information.
SWGFAST, Standard Terminology of Friction Ridge Examination 3-23-11 ver. 3.0
Level 2 detail
Ridge path, major ridge path deviations, and paths caused by damage such as scars.
Quantitative-Qualitative Friction Ridge Analysis, David R. Ashbaugh 1999 CRC Press
In Nov. 2004, the Third Level Detail working group (from the Standards Sub-Group of the
National Fingerprint Board of England and Wales) determined that it was not necessary to
subdivide the features used in friction ridge identifications. In England and Wales these terms are
no longer recognized and it has been established that they should not be used. See Features.
Individual friction ridge paths and associated events, including minutiae.
SWGFAST, Standard Terminology of Friction Ridge Examination 3-23-11 ver. 3.0
Level 3 detail
Ridge shape, relative pore location, and some accidental details.
Quantitative-Qualitative Friction Ridge Analysis, David R. Ashbaugh 1999 CRC Press
In Nov. 2004, the Third Level Detail working group (from the Standards Sub-Group of the
National Fingerprint Board of England and Wales) determined that it was not necessary to
subdivide the features used in friction ridge identifications. In England and Wales these terms are
no longer recognized and it has been established that they should not be used. See Features.
Friction ridge dimensional attributes, such as width, edge shapes, and pores.
SWGFAST, Standard Terminology of Friction Ridge Examination 3-23-11 ver. 3.0
Lift
An adhesive or other medium used to transfer a friction ridge impression from a substrate.
SWGFAST, Standard Terminology of Friction Ridge Examination 3-23-11 ver. 3.0
Light Wavelengths
Ultraviolet light wavelengths approx. 10nm-400nm
UV-C wavelengths approx. 200nm-280nm (dangerous)
UV-B wavelengths approx. 280nm-315nm (hazardous)
UV-A wavelengths approx. 315nm-400nm
Black light wavelengths approx. 345nm-400nm
Visible light wavelengths approx. 400nm-700nm
Purple wavelengths approx. 410nm
Blue wavelengths approx. 475nm
Green wavelengths approx. 510nm
Yellow wavelengths approx. 570nm
Orange wavelengths approx. 590nm
Red wavelengths approx. 650-700nm
Infrared light wavelengths approx. 700nm-1,000,000 nm
Visible light is sometimes referred to as white light. Technically speaking, white light is a
combination of all the colors in the visible light spectrum.
Lighting Techniques
Ambient, oblique or direct lighting are the most common types used in this field.
Lights Out
A computer process where the AFIS computer automatically extracts friction skin features,
searches the AFIS database, and effects an identification or exclusion based on a predefined
threshold score. No human is involved in the decision making process. This technology became
available around 2007 for tenprint operations.
Ligroine
See Petroleum ether.
SWGFAST, Glossary – Consolidated 09-09-03 ver. 1.0
Likelihood Ratios
The ratio comparing two different likelihood functions.
Lipids
Fats or fat-like substances that are insoluble in water.
Quantitative-Qualitative Friction Ridge Analysis, David R. Ashbaugh 1999 CRC Press
The major component of sebaceous sweat, which includes fats, oils and waxes.
Liquid Nitrogen
An element used in its liquid state (-195 degree C)for the separation of adhesive surfaces, as well
as to enhance the fluorescence of Zinc Chloride and Zinc Nitrate treated prints for visualization
and photography.
SWGFAST, Glossary – Consolidated 09-09-03 ver. 1.0
Liqui-drox
Fluorescent yellow solution used to develop friction ridge detail on the adhesive and nonadhesive sides of dark colored tape.
SWGFAST, Glossary – Consolidated 09-09-03 ver. 1.0
Liqui-nox ®
Detergent used in a solution to develop friction ridge detail on adhesive and non-adhesive sides
of tape; cleaning agent.
SWGFAST, Glossary – Consolidated 09-09-03 ver. 1.0
Limitation for Conclusions
A) Conclusions are the practitioner’s human interpretation, however, personal interpretations that
do not hold up to others are outside the bounds of drafting conclusions that are scientific in
nature. Interpretations must adhere to some standards (minimally, agency standards).
B) The ground truth is unknown.
C) The probability/likelihood of a feature or configuration of features in others is unknown.
D) The strength of any conclusion is dependent on the quantity and quality of the supporting data,
and the ability of the conclusion to hold up to rigorous scrutiny.
E) The best measure of strength in a conclusion is the acceptability, which is determined by the
demonstrability.
F) Reproducibility by others is not an indication of accuracy.
G) Case type may be relevant to whether or not a comparison is performed but is not relevant as
support behind a conclusion.
Locard, Edmond (1877-1966)
A major contributor in criminalistics in the early 1900’s. Locard trained as a medical doctor in
Lyon and did a thesis with Lacassagne. Lyon was at that time one of the best places for forensic
medicine in Europe (under the guidance of Lacassagne).
In 1910, while successor to Lacassagne as Professor of Forensic Medicine at the University of
Lyon, France, Locard established the first police crime laboratory.
In 1912, Locard established Poroscopy.
In the early 1910’s, Edmond Locard published his Tripartite Rule stating how many Galton points
were needed to make a positive fingerprint identification. Locard’s rule appears to have been
based on his own work as well as the work of others (Galton, Balthazard, etc.).
Due to some of Locard’s writings from the 1920’s and 30’s, the concept of the unintentional
transfer of different minute materials between objects became known as Locard’s Exchange
Principle (aka Locard’s Principle of Exchange). Locard was not the only person to recognize and
publish this information but he did articulate in better than others.
Locard’s Principle of Exchange (aka Locards Exchange Principle)
Edmond Locard’s Principle of Exchange states that when any two objects come into contact,
there is always transference of material from each object onto the other.
http://www.computing.surrey.ac.uk/ai/impress/ 06-19-2003
Lockheed-Martin 50k x 50k Study (1999)
See FBI / Lockheed-Martin 50k x 50k Study (1999).
Loop
A type of pattern in which one or more friction ridges enters an area, recurves, and flows out the
same side the friction ridges entered. Loops can be slanted to the right or left and be designated
as either radial or ulnar loops.
A pattern type in which one or more friction ridges enter upon one side, recurve, touch or pass an
imaginary line between delta and core and flow out, or tend to flow out, on the same side the
friction ridges entered. Types include left slant loops, in which the pattern flows to the left in the
impression; right slant loops, in which the pattern flows to the right in the impression; radial loops,
in which the pattern flows in the direction of the radius bone of the forearm (toward the thumb);
and ulnar loops, in which the pattern flows in the direction of the ulna bone of the forearm (toward
the little finger).
SWGFAST, Standard Terminology of Friction Ridge Examination 3-23-11 ver. 3.0
Loop – Radial
A type of pattern in which one or more friction ridges enter upon either side, recurve, touch or
pass an imaginary line between delta and core and flow out, or tend to flow out, on the same side
the friction ridges entered. The flow of the pattern runs in the direction of the radius bone of the
forearm (toward the thumb).
SWGFAST, Glossary 07-28-2009 ver. 2.0
Loop – Ulnar
A type of pattern in which one or more friction ridges enter upon either side, recurve, touch or
pass an imaginary line between delta and core and flow out, or tend to flow out, on the same side
the friction ridges entered. The flow of the pattern runs in the direction of the ulna bone of the
forearm (toward the little finger).
SWGFAST, Glossary 07-28-2009 ver. 2.0
Lophoscopy
The study of the development, the classification, and the identification of the prints left by the
papillary ridges of the skin.
http://users.tpg.com.au/kjw18/fingerprints/Referen/Fpterm/LTERM.HTM 11-12-2005
Loupe
A small magnifying glass.
Luminescence
Any form of light produced by a source other than heat, cool light (chemical, electrical).
Luminol
Luminol is a chemical that glows greenish-blue when it comes into contact with blood (and some
other items)— even traces that are years old. To be exact, it reacts to hemoglobin, an oxygen carrying protein in red-blood cells. Luminol is so sensitive, it can detect blood at 1 part per million.
In other words, if there is one drop of blood within a container of 999,999 drops of water, luminol
will glow.
http://dsc.discovery.com/fansites/onthecase/toolbox/tool_01.html