Forensic Light Source Applications
The
value that a forensic light source will bring to your department will be
measured by the significant increase in the number of suspects apprehended
and successfully prosecuted.
AFIS-APIS Applications -
RUVIS Applications
A forensic light source is a crime
scene investigator’s and lab technician’s tool for enhancing
observation, photography and collection of evidence including latent
fingerprints, body fluids, hair and fibers, bruises, bite marks, wound
patterns, shoe and foot imprints, gun shot residues, drug traces,
questioned documents, bone fragment detection, etc... It provides more
sensitivity than traditional methods thus increasing the amount of
evidence uncovered and the quality of the evidence photographed and
collected.
A forensic light source is made up
of a powerful lamp containing the ultra-violet, visible and infrared
components of light. It then filters down the light into individual color
bands (wavelengths) that enhance the visualization of evidence by light
interaction techniques including fluorescence (evidence glows), absorption
(evidence darkens), and oblique lighting (small particle evidence
revealed).
Utilizing
forensic light source techniques allows the latent print to be detected
with much more sensitivity (10-100 times more!) than the conventional
method of black powder dusting and lifting.
Latent
Fingerprint Detection
The primary application of a
forensic light source is for enhancing the detection of latent
fingerprints. The use of fluorescent enhancement processes that compliment
a light source greatly increases the types of surfaces from which a latent
fingerprint can be detected. Consider the difficulties of dusting and
lifting a print off of the following surfaces: thin plastic bags, rigid
duct tape, thin aluminum foil, heavily grained wood, concrete wall, brick,
printed glossy magazine pages, paper products, etc. Using traditional
methods, fingerprint evidence on these and other types of surfaces may go
undetected or even dismissed because they could not be detected with
enough detail. Forensic light source techniques have been successfully
utilized for revealing latent prints on these and many other types of
textured surfaces, backgrounds which mask ridge detail, fragile surfaces,
and contaminated surfaces. Different color bands (wavelengths) are
required for processing different types of surfaces making a forensic
light source with tunable or multiple color bands (wavelengths) a coveted
tool for any crime scene investigator. In many cases the background
surface will also glow under light source illumination. In these cases it
is necessary to tune to a color band (wavelength) of light that causes the
print to glow and not the background. The quality and quantity of evidence
revealed is proportional to the output power and the extent of color
tunability of the light source. This ability is exclusive to a forensic
light source, UV lights or Blue lights cannot offer this selectivity due
to their limited number of color bands (wavelengths) and low power.
Since
fluorescent techniques are very sensitive, only trace amounts of
fluorescent powder are required when dusting for prints at a crime scene .
It therefore leaves the scene much cleaner than when using black powder.
BODY
FLUIDS
Since body fluids like semen,
saliva, and vaginal fluids are naturally fluorescent, the use of a light
source offers a unique method for locating them. A crime scene
investigator can narrow down the specific locations of stains for
collection instead of testing entire, large pieces of evidence such as a
mattress, a carpet, a sheet, an article of clothing, etc... The dried body
fluids will actually glow under the light source illumination. Although
the body fluids will fluoresce under an ordinary UV black light, many
articles on which you would find them including clothing and sheets will
also glow and deter their detection. It is therefore necessary to tune to
visible color bands (wavelengths) to eliminate the background
interference. Considering you will be searching for body fluids on high
profile, capital crime cases, the more body fluid evidence you can reveal
the better. Again, the more powerful and more tunable your light source,
the more evidence you will uncover. Although blood does not glow in the
visible range, it has a unique color band (wavelength) under which the
blood stain will darken to enhance its contrast by approximately 4 times.
This is most effective in photographing blood prints because more of the
detail of the blood print will be revealed by the enhanced contrast.
Many
background surfaces glow under UV light and therefore a simple UV Black
light will not yield the quality and the quantity of evidence that can be
achieved with a tunable or multiple color band forensic light source.
HAIR
& FIBERS
Two light illumination methods can
be employed to locate hair and fibers with a forensic light source. First,
oblique or parallel lighting of a surface such as a floor or carpet with a
strong white light (the more powerful the better) will reveal small
particles like hair and fibers for collection. Second, some hair and
fibers will also glow under UV or visible light and will stand out
strongly for collection. For the best chance of collecting the maximum
number of hair and fibers at the crime scene, you need a powerful light
source that offers strong White light illumination as well as strong UV
and visible color bands (wavelengths); all of which are available only in
a forensic light source.
A
blue filtered flash light is limited by a single blue color band and even
more severely by the limited power output of a flash light.
BRUISES
/ BITE MARKS / PATTERN WOUNDS
A tunable or multiple color band
(wavelength) forensic light source reveal bruise and patterned wound
details that are invisible under normal white light illumination. Details
of a bruise pattern in a suspects palm can link a suspect to a weapon.
Furthermore, details of a bruise on a victim, for instance, a bite mark or
a shoe mark, can link a suspect to the victim. Multiple color bands
(wavelengths) are necessary because different colors penetrate to
different depths within the skin and therefore depending on the depth of
the bruise or wound you will need to vary the color band (wavelength) of
the instrument. Deep wounds may require infrared illumination to get
enough skin penetration.
Only
a forensic light source gives you the versatility of UV, visible, and IR
color bands for enhancing bruise or wound pattern detail.
QUESTIONED
DOCUMENTS
Inks have different formulations,
even within the same apparent color type. A tunable forensic light source
can be used to identify slight variations in ink type by viewing ink
responses as the color of the light is tuned through the visible and
infrared regions. Regardless of the skill of the forger, this examination
would reveal that 2 different pens were used on the document.
Pictures
and more Applications are on the way!
WHY
CHOOSE A SPEX CRIMESCOPE FORENSIC LIGHT SOURCE?
The SPEX Mini-CrimeScope 400
multiple color band (wavelength) forensic light source and the SPEX
CrimeScope CS-16 tunable forensic light source offer the following
advantages over other available forensic light sources:
MORE POWER: Both units offer
considerably more power output than even the nearest competitor. The
difference is visibly apparent and the advantage is clearly evident in the
ability to look at fainter evidence with our units. The reason for the
greater power is design. Both units take advantage of the latest in Liquid
Light Guide technology as well as incorporate the highest quality optics.
MORE COLOR BANDS: Both units offer
more color bands (wavelengths) than their competitors. The Mini-CrimeScope
400 offers wavelengths in multiples of 6 (6, 12, 18, etc.) with field
interchangeable 6 position filter wheels. The CrimeScope CS-16
incorporates 24 wavelengths for the UV, Visible and the IR, our nearest
competitor offers only 12 wavelengths. The CrimeScope also offers 15
positions for continuos tunability, more than any other light source
giving the highest overall intensity throughout the spectrum.
MORE USER FRIENDLY: The CrimeScope
line of forensic slight sources are the only units that offer true ONE
HAND OPERATION of color band (wavelength) selection; the Mini-CrimeScope
400 with its patented 6 position thumbwheel at the working end of the
light guide, and the CrimeScope CS-16 with its automated remote control at
the working end of the light guide. These are the only units on the market
which truly allow you to take advantage of the 2 meter light guides while
processing hard to reach areas like the insides of vehicles. Additionally,
ONE HAND OPERATION of the light source allows the other hand the
opportunity to dust or collect for evidence.
FULLY UPGRADEABLE: The CrimeScope
line of forensic light sources have the ability to be upgraded at any time
in the future. If a new application was developed for the light sources,
filters can be added to both units to cover that new application. This
upgradeability is cost effective, as you only need to purchase today what
wavelengths you need and can afford, upgrades allow you to spread the cost
of the unit over multiple budgets.
APPLICATION TARGETED DESIGN: The
CrimeScope line was not designed overnight. It evolved from a testbed to a
commercial product, to 2 distinct classes of light sources, and then
finally to the State of the Art forensic instruments you see today. Each
step of the way the designers worked with professionals in the forensics
field from the federal, state, and local levels to find out what the
community needed and wanted. The resulting CrimeScopes are the most
versatile, most rugged and easiest to use of any light sources ever
available. Because of their performance, SPEX has the most loyal users in
the field, returning to us for more units when they expand their
departments capabilities.
We are confident
the Mini-CrimeScope 400 and the CrimeScope
CS-16 are the best forensic light sources available, so sure that we
encourage side by side demonstrations and trials with our competitor's
units.
Copyright 2003 by SPEX Forensics
E-mail us now at Questions@mail.crimescope.com |