Crime Scenes
Basic Concepts
What happens at the crime scene?
– First Responder Priorities:
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Determine need for medical assistance
Confirm or pronounce death
Take steps to preserve and protect area
Secure and isolate the crime scene using ropes
or barricades
• Exclude all unauthorized personnel from scene
• Conduct a scene walk through
• Determine the lead investigator
Evaluation of the Area
• Determine the boundaries of the scene
• Establish the perpetrator’s entrance and exit
• Initial walk though of the scene to determine
the strategy for documentation of the entire
crime scene.
SKETCHING THE SCENE
• Rough Sketches
– Shows all items of physical evidence w/ number
assigned to each.
– Objects are located by distance measurements
from two fixed points.
– Distances marked must be accurate. All distances
are made with a tape measure.
– Each item is assigned a letter or number.
– The sketch shows a compass heading designating
north.
Back at the lab (after initial search)
• Finished Sketches
– Usually prepared with the aide of templates
– Usually drawn to scale
– Must contain all information contained in
the rough sketch
– Well constructed sketches are admissible
as evidence in a trial
Photographing the scene
• Overall Photos
– unaltered condition
– entire scene and surrounding areas,
including walls and points of entry and exit
– purpose is to include as much as possible
in one photograph
– goal - each important item is in at least one
photo
Photographing the scene
• Mid Range Photographs
– purpose - focus attention on - specific
object
– Use scales so photos can be admitted in
court
– Wounds and bruises should be
photographed with and without scales.
Photographing the scene
• Close up Photographs
• Purpose is show a specific aspect of an
object up close
• Show pattern of injuries
• Show weapons lying near the body
• After the body is removed, close up photos
of the area underneath
Notes from the scene
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Date/Time of arrival on scene
Name of investigators
Address/Description
Weather conditions (if outside)
Log of ALL activities including search,
sketch, photography, evidence
collection, etc.
Search Patterns
• Zone Search: A small area or room is
searched. It's used in homicides, rape,
drug and bomb searches.
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Search Patterns
• Ever Widening Circle: Used when only
1 person is available to search
• Also known as spiral
Search Patterns
• Straight Line Search: Used outdoors.
Many people stand shoulder to shoulder
and walk across the area in a straight
line.
Search Patterns
• Strip Search: Used when only a few
people are available to cover a large
outdoor area.
Search Patterns
• Grid Search: Covers a large area.
Divide area into a grid and search each
grid. Repeat perpendicular to first grid.
Types of crime scenes
• Primary - where crime was committed
• Secondary - where additional physical
evidence has been found
Also they can be classified by
• Type of crime (ie. Robbery, assault…)
• Condition (ie. Organized, disorganized)
• Location (ie. Indoors)
The end of notes for today