Transcript The Crime Scene - Douglas County

Investigative Photography
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Physical evidence is any object that can establish
that a crime has been committed or can link a
crime and its victim or its perpetrator.
Forensic science begins at the crime scene. The
investigator must recognize physical evidence &
properly preserve it for laboratory examination.
The evidence must be kept in its original
condition as much as possible.
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Secure & Isolate the Crime Scene
First priority is medical assistance to individuals &
arresting the perpetrator.
 Ropes or barricades and guards will prevent
unauthorized access to the area.
 Every person who enters the crime scene has the
potential to destroy physical evidence.
 The lead investigator evaluates the scene & determines
the boundaries. They do an initial walk through &
develop a strategy.
 All items must be documented & photographed.
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3 methods of
crime-scene
recording:
photography,
sketches, &
notes
Ideally all 3
should be used
 Scene
 Multiple
views
 Entrances
 Exits
 Windows
Evidence
Close ups
Perspectives
Multiple
angles
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The crime scene should be unaltered, unless
injured people are involved, objects must not be
moved until they have been photographed from
all necessary angles.
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If things are removed, added, or positions changed the
photographs may not be admissible evidence.
Photograph completely
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Area where crime took place & adjacent areas
Various angles
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If crime scene includes a body:
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Take photos to show body’s location & position relative
to the whole crime scene
Take close-up photos of injuries & weapons lying near
the body
After the body is removed, photograph the surface
underneath.
When size is significant, use a ruler or other
measuring scale
Digital cameras allow for enhancement &
examination in fine detail.
Videotaping a scene is also becoming popular.
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1. To record the original scene and related
areas
2. To record the initial appearance of
physical evidence
3. It will provide investigators and others
with this permanent visual record of the
scene for later use
4. Photographs are also used in court trials
and hearings
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1. Three major points of qualification of a
photograph in court
a. Object pictured must be material or relevant to
the point in issue
b. The photograph must not appeal to the emotions
or tend to prejudice the court or jury
c. The photograph must be free from distortion and
not misrepresent the scene or the object it
purports to reproduce
2. You do not need to be an expert in photography to
take crime scene photographs or testify about them
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Any picture an officer takes may wind up in
Court.
You will be safe if you keep this in mind for
every photo you shoot.
Experience has shown that attention to a
few simple rules can make pictures
acceptable to most judges.
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Purpose
a. To show the scene exactly as it was when
you first saw it
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(1) If something was moved before you arrived,
don't try to reconstruct the scene as it was.
The photographs should show the scene as
you found it
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a. First discuss the crime, evidence and
photographs needed with other investigators
at the scene
b. Be careful not to destroy any evidence
while taking the photographs
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(1) Exterior of the building where the crime
occurred and in some cases the whole locale
(2) Aerial photographs of the scene and the
surrounding area can be useful in some types
of cases
(3) Original series of photographs should
also show all doors, windows and other means
of entrance or exit
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(1) Begin with a view of the entrance
(2) Then photograph the scene as it appears
when you first step into the room
(3) Next, move around the room to get
photographs of all the walls
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(a) These photographs should also show the
positions of any potential items of evidence
(4) Include photographs of other rooms
connected with the actual crime scene
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1. Take two photographs of each item of
evidence
a. One should be an orientation (midrange) shot to
show how the item is related to its surroundings
 b. The second photograph should be a close-up to
bring out the details of the object itself
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2. Measuring and marking devices
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a. Take two photographs if a marking or measuring
device is used
 (1) One photograph without the device, the other
with the device
 (2) So the defense can't claim that the scene was
altered or that the device was concealing anything
important
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Each crime scene has unique characteristics
and the type of photographs needed will be
determined at the scene by the investigator
familiar with the crime.
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1. Use color film
2. Photographs (example: homicide inside a
residence)
a. Exterior of the building
 b. Evidence outside the building
 c. Entrance into the scene
 d. Room in which the body was found
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 e. Adjoining rooms, hallways,
stairwells
 f. Body from five angles
 g. Close-up of body wounds
 h. Weapons
 i. Trace evidence
 j. Signs of activity prior to the
homicide
 k. Evidence of a struggle
 l. View from positions witnesses
had at time of the crime
 (1) Use a normal lens
 m. Autopsy
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If there is any
doubt, photograph
the scene as a
homicide
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1. Photographing injuries
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a. Face of victim in the photographs
b. Bruises
c. Bite marks
 (1) Orientation shot
 (2) Close-up at 90 degree angle to avoid distortion
 (3) Ruler in same plane as bite mark
 (4) Focus carefully
 (5) Bracket exposures
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Fingerprints
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When to photograph
fingerprints
 a. Before lifting on major cases or
if the latent may be destroyed
when lifting
 b. To bring out detail in a latent
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1. Footprints and tire tracks
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Procedure
 (1) Take an orientation photograph
to show where in the scene the
impression is located
 (2) Take a close-up for detail
 (a) Use a scale on the same plane as the
impression
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1. Use color film
2. Orientation photographs to show locations
of bloodstain evidence at the scene
3. Close-up photographs to show detail
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a. Use a scale on the same plane as the bloodstain
b. Keep the film parallel to the plane of the
bloodstain
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Does this picture reveal the true position of
the witness to the crime?
Do the skid marks seem longer or shorter in
the viewfinder than they are in real life?
How large is the lead pipe used as a weapon?
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Shoot most pictures with the camera at eye
level.
This is the height from which people
normally see things and that makes it easier
to judge perspective.
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One practical way to assure complete
coverage and to provide correct perspective
is to follow the FOUR CORNER APPROACH.
(Fig.1)
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Once photos are taken, sketch the scene.
A rough sketch is a sketch, drawn at the crime
scene, that contains an accurate depiction of the
dimensions of the scene & shows the location of all
objects having a bearing on the case.
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All measurements are made with a tape measure
Show all items of physical evidence
Assign each item a number or letter and list it in the
legend
Show a compass heading designating north
A finished sketch is a precise rendering of the
crime scene, usually drawn to scale.
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Computer-aided drafting (CAD) has become the
standard.
Rough-sketch diagram of a crime
scene. Courtesy Sirchie Finger
Print Laboratories, Inc.,
Youngsville, N.C.,
www.sirchie.com.
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Note taking must be a constant activity
throughout the processing of the crime scene.
The notes may be the only source of information to
refresh memory.
Tape-recording notes at a scene can be
advantageous – detailed notes can be taped much
faster than they can be written.
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Once found, physical evidence must be collected
& stored in a way that preserves its integrity for
forensic comparison & analysis.
The search for physical evidence must be
thorough and systematic, even when suspects are
immediately seized.
A forensic scientist is not usually needed at the
scene unless the evidence is complex or it is a
major crime.
Some police agencies have trained field evidence
technicians.
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One person should supervise & coordinate.
Include all probable entry & exit points in search
What to search for will be determined by the
particular circumstances of the crime.
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Examples
 Homicide
 Hit-and-run
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In most crimes, a search for latent fingerprints is
required.
(a) Spiral
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(b) Strip/Line
The crime scene
coordinator may
choose from a variety
of crime scene search (c) Grid
patterns based upon
the type and size of the
crime scene.
(d) Zone/Quadrant
(e) Pie/Wheel
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Physical evidence can be anything from massive
objects to microscopic traces.
It may be necessary to take custody of all clothing
worn by the participants in a crime.
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Handle carefully & wrap separately to avoid loss of trace
evidence.
Critical areas of the crime scene should be
vacuumed & the sweepings submitted to the lab
for analysis.
Mobile crime-scene vehicles carry supplies to
protect the crime scene; photo, collect, & package
evidence; & develop latent fingerprints.
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The integrity of evidence is best maintained when
the item is kept in its original condition as found at
the crime scene.
The entire object should be sent to the lab.
If evidence is found adhering to a large structure,
remove specimen with forceps or other appropriate
tool.
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In the case of a bloodstain, one may either scrape the
stain off the surface, transfer the stain to a moistened
swab, or cut out the area of the object containing the
stain.
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Each different item or similar items collected at
different locations must be placed in separate
containers.
Packaging evidence separately prevents damage
through contact and prevents cross-contamination.
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Medical examiner or coroner carefully examines
the victim to establish a cause & manner of death.
Tissues are retained for pathological &
toxicological examination.
The following are collected & sent to the lab:
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Victim’s clothing
Fingernail scraping
Head & pubic hairs
Blood (DNA typing)
Vaginal, anal, & oral swabs (in sex-related crimes)
Recovered bullets from the body
Hand swabs from shooting victims (for GSR analysis)
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Forceps
Unbreakable plastic pill bottles w/ pressure lids
Manila envelopes, glass vials, pill boxes
Paper bags are better than plastic…why?
Fire evidence must be kept in an airtight container
to prevent evaporation of petroleum residues
Clothing must be air-dried & placed in individual
paper bags.
http://www.crimescene.com/ecpi/evidence_collection.shtml
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Chain of custody is a list of all people who came
into possession of an item of evidence.
Chain must be established whenever evidence is
presented in court as an exhibit.
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Failure to do so may lead to ? Regarding authenticity &
integrity of evidence.
All items should be carefully packaged and
marked upon their retrieval at crime sites.
Normally, the collector’s initials & date of
collection are inscribed directly on the article.
The evidence container must also be marked with
collector’s initials, location of evidence, & date of
collection.
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The examination of evidence often requires
comparison with a known standard/reference
sample.
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A standard/reference sample is physical evidence whose
origin is known, such as blood or hair from a suspect,
that can be compared to crime scene evidence.
Such materials may be obtained from the victim, a
suspect, or other known sources.
The presence of standard/reference samples
greatly facilitates the work of the forensic scientist.
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Bloodstained evidence must be accompanied by a
whole-blood or buccal swab s/r sample obtained
from all relevant crime-scene participants.
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A buccal swab is a swab of the inner cheek, performed to
collect cells for use in determining the DNA profile of an
individual.
Some types of evidence must also be accompanied
by the collection of substrate controls.
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Normally collected at arson scenes.
A substrate control is uncontaminated surface material
close to an area where physical evidence has been
deposited; used to ensure that the surface on which a
sample has been deposited does not interfere with
laboratory tests.
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Evidence is submitted to the lab either by personal
delivery or by mail shipment.
Most labs require that an evidence submission
form accompany all evidence submitted.
Enables the lab analyst to make an intelligent &
complete examination of the evidence.
 Provide a brief description of the case history so the
examiner can analyze in a logical sequence.
 The particular kind of examination requested for each
type of evidence should be delineated.
 A list of all items submitted must be included.
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Forensic Pathology involves the
investigation of unnatural,
unexplained, or violent deaths.
Forensic pathologists in their role as
medical examiners or coroners are charged
with determining cause of death.
 The forensic pathologist may conduct an
autopsy which is the medical dissection
and examination of a body in order to
determine the cause of death.
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The increasing spread of AIDS and hepatitis B has
sensitized the law enforcement community to the
potential health hazards that can exist at crime
scenes.
In reality, law enforcement officers have an
extremely small chance of contracting AIDS or
hepatitis at the crime scene.
The International Association for Identification
Safety Committee has proposed guidelines to
protect investigators at crime scenes containing
potentially infectious materials that should be
adhered to at all times.