AGONCILLO COLLEGE INC.
Poblacion, Agoncillo, Batangas
Tel: (043) 7740011 / 0921- 739-3635/ 0916- 327-
9908
Email: agoncillocollege_inc@yahoo.com
MODULE
PERSONAL IDENTIFICATION
WEEK 2- March 29
DAY- Sunday
TIME- 3hours
ACTIVITY- Answer the following questions (A) and (B).
DEADLINE- March 31
LATENT FINGERPRINT
A latent fingerprint generally refers to the print or impression found in the crime
scene. Although, the term “Latent” connotes something hidden, but the term likewise
refers to any print in the crime scene, including those visible or partially visible
impression.
Three Classification of crime scene print
1. Patent Prints- These are impression in the crime scene that can be directly
seen by a naked eye. This impression is caused by obvious contaminants
such as blood, grease, dust and some other substance which may be visible
after impression.
2. Plastic prints- These are ridge impression left on soft material such as wax,
patty, butter, soap, plastic tape, etc.
3. Latent prints- These are impression caused by the transfer of oil or
perspiration from the pores of the fingers to the surface of an objects.
The sections of these glands are as follows:
GLAND Inorganic compounds Organic Constituents
1. Eccrine Chlorides Amino Acids
Metal Ions Urea
Ammonia Lactic Acids
Sulphates Sugars
Phosphates Creatine
Choline
Uric Acids
2. Sebaceous Fatty Acids
Glycerides
Hydrocarbons
Alcohols
3. Apocrine Iron Proteins
Carbohydrates
Cholesterol
Water is the first component to be lost from most fingerprints. Since latent
prints are not visible to the naked eye, and substantially consist of only the natural
secretions from human skin. Such print requires treatment to cause them become
visible. This treatment is called latent print development.
METHODS OF DEVELOPING LATENT PRINTS
A. Powder Methods
- It is the application of finely ground, colored powder to nonporous object to
make latent prints visible. This method is more effective for newer prints
and is/are found on hard, dry and smooth surface.
- Fingerprint powders vary in color, but the most common are black, white
and gray. The powder to be used must be in contrast with the color of the
background of the surface. Dark powders are for light surfaces and light
powder are for darker surfaces.
Powders are also manufactured with the following formulations:
a. Oxides- This powder is ideally used on painted or smooth surfaces including
plastics. Oxides powder is extremely sensitive to moisture, particularly
sebaceous or oily secretions.
b. Metallic’s- This powder is most effective on plated or polished surfaces such
as silver and chrome.
c. MAGNETICS- These are powders having magnetic properties and therefore,
it must not be used on surface containing iron or steel.
d. Combinations- This powder is a combination of oxide and metallic powders
in such a way that it can be used on any surface whether dark or light.
e. Fluorescents- Fluorescent powder are oxide in nature and can only be used
on painted or smooth surfaces, but these powders are designed to overcome
the problem on multi- colored surfaces.
LIFTING DEVELOPED LATENT PRINTS
After the latent print had been developed using the fingerprint powder and
after it has been properly photographed there is need to lift and collect the said print.
B. Chemical Methods
1. Ninhydrin- is a biological stain that will react to animo acid present in latent
print; even the print is several years old this chemical is used to develop
latent prints on porous surfaces; especially paper and it must be used only
with adequate ventilation.
2. DFO (1, 8- Diazafluoren-9 – one) - DFO is a Ninhydrin analog that
reportedly will develop 2 ½ times the number of prints as Ninhydrin alone.
Latent print development using DFO can be accelerated by using
controlled heat.
3. Silver Nitrate- Silver Nitrate solutions are light sensitive and will react with
the silver chloride or salt residue present in the latent print. When latent
print is treated with this chemical and exposed to light, a dark brown print
will appear.
4. Physical Developer- will react to sebaceous components of latent print
residue and will give a silver- gray color of the print. It is usually applied
after the DFO and/or ninhydrin methods.
5. Small Particle Reagent (SPR)- is a suspension of fine molybdenum
disulfide particles (dark) or titanium dioxide (light). Small particle reagent
adheres to fatty substance of latent fingerprints and is useful rain- soak
vehicles bodies, windows and window trim, etc. The latent print will turn to
gray color when applied this reagent.
c. VAPOR METHODS
1. Iodine Fuming Methods- Iodine fume reacts with the greasy or oily and fatty
substances of latent print. Iodine fuming is ideally use when prints are still fresh.
- When Iodine is exposed to heat, iodine crystal will undergo a process
known in as sublimation.
2. Cyanoacrylate (super glue) fuming- Cyanoacrylate are super glue. The
fames of super glue will react to the water present in the latent print residue. The
moment that the fumes will come to contact with latent print, it forms a hard
compound that conform to the ridges.
QUESTIONS (A)
1. What is the distinction between latent print and patent print?
2. Why do people leave a fingerprint when they touch objects?
3. How does magnetic powder differ from non- magnetic powder?
4. What do you think are the advantages of chemical methods over powder
methods?
5. What are the chemical compositions of small particle Reagent (SPR)?
6. What is SUBLIMATION?
7. What is the value of Super Glue in fingerprint development?
FINGERPRINT COMPARISON
It is the process of a careful and a through comparison of two or more
fingerprints into its minute ridge characteristics to establish its similarities or
dissimilarities.
After the latent print has been processed and developed from the crime
scene, the next responsibility of the fingerprint technician is to look for a possible
match of such questioned print with those available standard prints on file. Standard
prints are either collected or requested prints. Collected standards refers to those
fingerprint collected by law enforcement agencies from a previously arrested law
violators or those prints collected by police when one applies for police clearances.
In fingerprint comparison, the ridge characteristics of the questioned print will
be compared with ridge characteristics of the standard print. A point of similarities
must be properly established to obliterate some doubts.
All the process of comparison are govern by the number of identical
characteristics of the ridges in which most courts consider 8 to 12 points of identity is
sufficient for convincing identification.
QUESTIONES (B)
Define the following:
1. What are the Methods of Comparison of Latent Print and Standard Print?
2. What is Ordinary Method?
3. What are the Kinds of Ordinary Method and their definition?
GINA C. CAMBONGGA., RCrim,
Prepared by:
