Crime Scenes

Basic Concepts

What happens at the crime scene?

– First Responder Priorities:• 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

• 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.

1 2

3 4

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