If you leave something out of a sketch, such as a window, a piece of furniture, or a light fixture, be prepared to explain the omission at the
deposition or trial.
Additional information to include in the sketch:
compass direction, relevant items of physical evidence
along with the location of such items indicated by measurements from at least two fixed points or other
methods, and a legend of the symbols used to identify objects or points of interest on the sketch.
Sketches should include the statement
"not to scale"
unless you are prepared to testify that every item is precisely drawn to scale on the sketch.
A sketch that is drawn to scale shows the objects with accurate sizes except
that they have all been reduced or enlarged by a certain
amount relative to each other.
help to document the relative positions of evidence items in the crime scene. Place evidence markers next to each piece of evidence within the crime scene after initially photographing the scene and developing your initial sketch.
(diagrams and sketching) Include the case number, location, date and time, and your name when submitting
Visible evidence can include
bruises, lacerations, broken bones, gunshot wounds, and trace or transfer evidence.
The person you are photographing has to be a
suspect, witness, or victim of a crime to support taking a
A suspect does not have the right to
refuse photographing injuries such as scratches from the
victim or blood evidence.
Apply the same photographic perspectivesโoverall, midrange, and close-upโwhen documenting injuries
and evidence on
people!! Use a scale or identifier to document the extent of the injury.
If you need to take photographs of an injury to any external genital organs, have an officer of the
same gender as the victim observe and photograph the injuries. It may be prudent to have a witness present
when photographing these types of injuries.
(person) Include the case number, location, date and time, and your name when submitting a
photograph of a person
Dr. Edmond Locard (1877-1966), a pioneer in forensic science, formulated the fundamental principle of forensic science:
"Every contact leaves a trace." Referred to as
Locard's Exchange Principle, this contends that everyone who enters a crime scene will both bring something into and take something from it.
The job of a crime scene analyst is to
determine what evidence at the scene belongs to the criminal and not to the victims or witnesses.
A few examples of evidence that you may find and collect at a crime scene are
fingerprints, shoe prints, blood, fibers, hair, tool marks, paint scratches, broken glass,
bodily fluids, controlled substances, electronics equipment and computers, firearms,
broken or damaged materials, tire tracks, documents, and bones.
To avoid contamination,
change gloves between
collecting each piece of evidence collected for DNA analysis.
wet evidence, such as items soaked with bodily fluids or living plant material, must either be
air-dried, packaged in breathable containers such as paper bags, or both.
Use one or more of the following search patterns: (5)
strip/line search pattern: grid search pattern: pie/wheel search pattern: spiral search pattern: zone/quadrant search pattern:
โข strip/line search pattern:
usually used outside by several people. Divide the
search area into lanes. Have one or more people search each lane by moving in both directions, examining all areas.
โข grid search pattern:
often used indoors; a variation of the strip/line search
pattern. Searchers overlap a series of lanes in a cross pattern, making the search
more methodical and thorough
โข pie/wheel search pattern:
entails dividing the area into a number of wedge-shaped
sections, which are usually searched using the strip/line search pattern. Use this method for extremely large search areas.
โข spiral search pattern:
usually used outside by one person. The searcher begins
at a certain point and walks in increasingly larger circles to the outermost boundary of the search area.
โข zone/quadrant search pattern:
used for vehicle searches, outdoors, or a large
area. Divide the area into four different sections and search each using one of the patterns above.
is the process of microscopically
analyzing trace evidence, such as paint, glass, and cloth fibers, to
determine a possible source or origin. Microanalysis can
identify and compare other materials such as textile fibers, plastics, duct tape, lamp filaments, and fractured, torn, or cut items.
Fibers can come from
clothing, carpet, rope, automobile carpeting, upholstery, or other common articles.
The relation that fiber evidence has to the victim, suspect, or the crime scene is crucial
evidence in many cases.
Broken windows, torn screens, or other sharp
snag fibers during a subject's entry into or exit from a building.
When the inside of a vehicle is part of a crime scene, examine the
seat belts, airbag, steering wheel, and other components for fibers.
Holding a flashlight to create side light and using a
magnifying glass may help you
spot fiber evidence.
Comparing and matching fragments from a broken piece of glass can establish a
common origin and a relationship between the victim, the suspect, and the crime scene.
The crime laboratory can analyze the glass pieces and compare characteristics, such as
color, density, thickness, and type of glass (tempered window, non-tempered, headlight, and bottle) to match and identify its origin.
if a suspect or victim is near a piece of glass when it breaks, glass fragments may
contaminate the person's body, shoes,
The direction of force or the order in which glass is broken can determine on which
side of the glass the suspect stood, thus establishing the suspect's entry or exit path.
Sometimes, soil from a crime scene attaches to a suspect's or victim's clothing, shoes, tires, or other objects, and the person transports it to
blood, semen, saliva, bones, teeth, body tissues, hair, DNA,
fingerprints,tire tracks, footwear
impressions,footprints, bite marks, tool marks
weapons, projectiles, gunshot
cases, tool marks, database
computers,cell phones, PDA, thumb drives, external hard
drives, CDs, DVDs,VHS tapes, digital cameras, answering
machines,digital recording devices
checks, bank statements, address books, wire transfers, credit cards, phone bills, photographs
or cameras, photo copies
materials that could be transferred during the commission of a violent crime. These trace materials include human hair, animal hair, textile fibers and fabric, rope, feathers, soil, glass, and building materials.
blood, saliva, urine, semen, perspiration, vaginal
secretions, feces, or vomit, You may find this evidence at a:
murder, aggravated battery, sexual assault, hit-andrun,
and burglary scenes.
Crime laboratory experts in serology can identify these
body fluids and, if needed, conduct further
testing using DNA analysis.
Other pieces of evidence that may contain saliva, and require examination, are
cigarette butts, drinking straws, soda and beer
cans, masks, bottles, etc. Bite marks may also contain saliva.
Experts can analyze the direction of blood spray or
spatter to determine the type of
weapon, the direction of the attack, and the relative size of the attacker.
You may need to collect the entire
damaged surface and submit it to the laboratory for comparison with the suspect's
Comparing the fracture sites of two or more parts of a broken, torn, or cut object and determining
whether they were once whole can provide
strong evidence in court.
Do not attempt to reconstruct the items
or process latent prints from the pieces before
Surface footwear impressions or tire prints can remain on
wood, tile, paper, or paint, or in dust,
blood, or grease
Teeth can provide
dental evidence in the form of bite mark impressions that can lead to the identity of the
are transferred from the friction
ridges on fingers by a FOREIGN SUBSTANCE (not a body residue), like
blood, paint, or dirt, and are
is a MOLDED or IMBEDDED fingerprint created by touching an impressionable surface, such as wet paint or mud that you can easily see.
are among the most valuable types of physical evidence and one of the most common types
of evidence you will recover at a crime scene. Although generally invisible to the naked eye, latent prints result
from body residues left behind when the friction ridges of the hands or feet make contact with a surface.
When collecting evidence, wear
gloves to prevent leaving your own latent prints. Take care to avoid smudging or smearing existing latent prints when handling and packaging evidence.
The most common way to process latent fingerprints is by
dusting them with one of several types of powder, which
develops the print and makes it visible. Use a fine brush to apply dust to the surface on which someone placed a
print. Lift a found print from its original surface with clear or frosted tape, then attach it to a small note card.
Follow these guidelines when dusting for and lifting latent prints:
1. Wear gloves to avoid contaminating the area with your own fingerprints. Be careful not to wipe possible
prints off the surface.
2. Hold a flashlight at an angle, and look for obvious signs of a latent print.
3. Take your brush and lightly dab into the powder once you find a target area.
4. Tap and twirl the excess powder off the brush in the jar of powder. Use it sparingly because it tends to
get on everything. It is better to use too little than too much.
5. Lightly brush from side to side, or swirl the brush, on the target area. If the powder adhered to the print
is too thick, brush off the excess powder with a clean brush and adjust the amount of powder.
6. When you find a print, apply the tape in the following manner:
a. Place a suitable fingerprint card on a flat surface nearby so that it is ready for the print you lift with
b. Turn under the end of the lifting tape to form a tab.
c. Extend the tape to a distance long enough to cover the print.
d. Place the rolled end of the tape just above the latent print, but keep it off the print.
e. Make sure that you do not trap foreign matter or air bubbles under the tape.
f. Smooth from the tabbed end of the tape back toward the rolled end or vice versa. Use your finger,
pen, or another object to smooth out the tape and release any trapped air. It is the same basic
process as putting a decal on a window. With time and practice, you will develop your own
technique for applying the tape.
7. Slowly lift the tape containing the developed prints from both ends, being careful not to touch the tape
to another surface, such as your gloves.
8. Carefully place the tape on the fingerprint card in the same way that you placed the tape over the latent
print. Place the print in the designated place on the correct side of the card.
9. On the back of the fingerprint print card, record the date, case number, the location within the crime
scene where you retrieved the fingerprint and any other information your agency's policies and
procedures require. Be careful not to damage the print.
10. Follow your agency policies and procedures to submit print evidence.
allow fingerprint analysts to distinguish between prints belonging to either the victims
and witnesses or the possible suspects. To make this distinction, take inked fingerprints from innocent parties,
who may have been at the crime scene, in order to eliminate their prints from the scene.
put the magazine and the
ammunition in a
separate container, then place them both in the firearm or evidence box.
Before placing the firearm in the box,
carefully examine it to identify the manufacturer, country of origin, serial number, model number, and caliber.
This will tell you if the firearm is lost, stolen, or found?
running the firearm serial number through FCIC/NCIC database
Conduct an eTrace database search through the
Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) to determine the original owner of the firearm or the firearms dealer.
Analysts can examine fired bullets
cartridge cases, and shotgun shells to determine if the suspect's weapon fired them. They examine bullets recovered from a crime scene to identify the make and type of weapon involved. An analyst may also examine the crime scene for the presence of gunpowder and shot pellet spread to determine firing distance. Analysts can identify tool marks, aftermarket modifications, and serial number restoration