Chp. 2

Chp. 2

The Crime Scene

Part I

1

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Please Do Now #4

Explain what you think happened?

Please write at least 5 lines in your composition book.

Chapter 2: THE CRIME SCENE

“Oh, how simple it would all have been had I been here before they came like a herd of buffalo and wallowed all over it.”

—A. Conan Doyle, in The Boscombe

Valley Mystery, 1892

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Crime solving is a jigsaw puzzle that must be pieced together

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Good Investigators Have…

Patience Thoroughness Accuracy Ethics Respect Versatility Objectivity

(7)

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Complex Reasoning Skills Necessary to Work Through and Solve Crimes:

Deductive and Inductive Reasoning

Classifying Comparing and

Contrasting Problem Solving Analyzing Perspectives Constructing Support Error Analysis

What skills do you think are necessary to work through and solve crimes?

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I. Physical Evidence

1. Any object that can establish that a crime has been committed OR

2. Can link a crime and its victim or its perpetrator

Its presence first MUST be recognized at the crime scene if it is to be used effectively for aiding the investigator.

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Physical Evidence and the Crime Scene

• Forensic science BEGINS at the crime scene.

• An investigator must 1) recognize physical evidence2) properly preserve evidence for lab examination

• If this is not done, no amount of sophisticated laboratory instrumentation or technical expertise can salvage the situation.

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What are CSI Determinations? (6)

What crime has occurred? Where did it happen? Who committed the crime? When was the crime perpetrated? Why did the crime happen? How was the crime committed?

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CORPUS DELICTI“Body of the Crime”

You must prove that a crime occurred that the person charged with the crime was responsible for the

crime Top Reasons for Committing a Crime

Money Revenge Emotion—love, hate, anger

Source of Evidence Body Primary and/or Secondary Crime Scene Suspect(s)

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CRIME SCENE TEAM

A group of professional investigators, each trained in a variety of special disciplines.

Team Members First Police Officer on the scene Medics (if necessary) Investigator(s) Medical Examiner (if necessary) Photographer and/or Field Evidence Technician Lab Experts

Lab Experts:

pathologist serologist

DNA expert toxicologist

forensic odontologist forensic anthropologist

forensic psychologist forensic entomologist

firearm examiner bomb and arson expert

document and handwriting experts fingerprint expert

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CRIME SCENE INVESTIGATION

Based on the scientific method and the Locard Exchange Principle, logic and forensic techniques

**Involves: Recognition—scene survey, documentation,

collection Identification—comparison testing Individualization—evaluation and interpretation Reconstruction—reporting and presenting

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Recording the Crime Scene

Investigators have only a limited amount of time to work a crime site in its untouched state

Opportunity to permanently record the scene in its original state must not be lost

Such records will not only prove useful during the subsequent investigation but are also required for presentation at a trial in order to document the condition of the crime site and to delineate the location of physical evidence.

Thoroughly document every step of the investigation with an appropriate method.

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PROCESSING ACRIME SCENE

1. Isolate and secure the scene

2. Document the scene3. Search for evidence4. Collect and package

evidence, maintaining the chain of custody

5. Submit evidence to the crime lab

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Crime Scene Management and Processing

The crime scene must be identified The scene must be secured Access and departure must be logged Access must be restricted to authorized

personnel A chain of custody MUST be established

for every piece of evidence from collection to inspection

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**5 STEPS OF CRIME SCENE PROCESSING

Each step requires numerous procedures to be performed at certain times:

1. Responding to the crime scene

2. Crime scene photography

3. Crime scene diagramming

4. Collection of physical evidence

5. Processing the scene for fingerprints

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Crime Scene Processing Order

Photography Search and mark evidence Collection of evidence

• Hair and fibers• Serological specimens• Other physical evidence

Fingerprinting Alternate light sources Chemical processing Re-Search Post evidence recovery photographs

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Crime Scene Photography and Diagramming

Crime scene photography completed BEFORE moving or

collecting any evidence

Crime scene diagramming The ROUGH SKETCH (with measurements)

must be completed BEFORE moving anything and a complete evidence list and sketch legend is completed

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Collection of Physical Evidence

The scene must be legally searched for evidence that is both seen and unseen.

When evidence is found, it must be documented fully, collected properly and packaged correctly to maintain its evidentiary value.

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Processing the Scene for Fingerprints

Fingerprinting the crime scene is usually performed last. WHY?

Those items or surfaces that need processing will have to be protected from contamination until after the scene has been processed.

There are exceptions to this which are determined by the circumstances of each scene.

Fingerprint powders will contaminate the scene

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FIRST OFFICERON THE SCENE

A Assess the crime scene and assist those hurt

D Detain the witness

A Arrest the perpetrator

P Protect the crime

scene

T Take notes

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CRIME SCENE SURVEY

Walk-through—performed by the crime scene investigator, the first officer and sometimes the lead detective

Purpose: Mentally prepare a reconstruction theory Note any transient or conditional evidence that could change over time. Note weather conditions Note points of entry or exit, as well as paths of travel within the crime

scene Record initial observations of who, what, where, when, and how Identify special needs within the crime scene for personnel, precautions

or equipment and notify superior officers or other agencies

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Record the Crime Scene

**Recording Methods: KNOW1. Photography (still and sometimes video)

2. Sketches

3. Notes

Ideally all three should be employed However, personnel and monetary limitations

may prohibit the utilization of photography at every crime site

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PHOTOGRAPHY

The most important prerequisite for photographing a crime scene is for it to be in an unaltered condition.

Unless there are injured parties involved, objects must not be moved until they have been photographed from all necessary angles.

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PHOTOGRAPHY

Photograph physical evidence as it is found, showing its position and location relative to the entire scene

Once overviews are taken, close-ups should be taken to record the details of the object itself. When the size of an item is of significance, a

ruler or other measuring scale may be inserted near the object and included in the photograph as a point of reference.

Click for making a photographic record

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VIDEOTAPING

Should include the entire scene and the immediate surrounding area

Long shots as well as close-ups taken in a slow and systematic manner

Have one crime scene investigator narrate while another does the actual taping

CANNOT be used in place of still photography

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SKETCHES

Once photographs are taken, the crime-scene investigator will sketch the scene.

Rough Sketch —A draft representation of all essential information and measurements at a crime scene. Drawn at the crime scene. It shows all recovered items of physical evidence, as well as other important features of the crime scene.

Finished Sketch —A precise rendering of the crime scene, usually drawn to scale. Not normally completed at the crime scene. Unlike the rough sketch, the finished sketch is drawn

with care and concern for aesthetic appearance.

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CRIME SCENE SKETCH

Date: August 14, 2005 Criminalist: Ann WilsonTime: 11:35 am Location: 4358 Rockledge Dr, St. Louis, Mo.

N

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FINISH SKETCHESsee figure 2—5 p 48

Made with care and concern for aesthetic appearance - must have information from the rough sketch. WHY?

Computer-aided drafting (CAD) has become a standard method for reconstructing crime scenes from rough sketches (see p. 49 Fig. 4—6)

To be admissible evidence in court

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Photography and Sketches

4 types of photographs

1. Forensic

2. Medical

3. Evidentiary

4. Police “snap” shots

Sketches

Indicate measurements Use only the English system

Locate evidence Include

date location and case #

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NOTES

Note taking must be a constant activity throughout the processing of the crime scene.

Must include a detailed written description of the scene with the location of items of physical evidence recovered.

Must identify: the time an item of physical evidence was discovered. by whom. how and by whom it was packaged and marked. the disposition of the item after it was collected.

This written record may be the only source of information for refreshing one’s memory in court.

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Crime Scene Notes

Concise Legible Accurate Objective (contain no theories, opinions, or

speculation) Are subject to legal discovery Are legally required in some jurisdictions and

must be maintained and surrendered

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**DOCUMENTATION**

Notes—date and time, description of the location, weather and environmental conditions, description of the crime, location of the evidence relative to other key points, the names of all people involved, modifications that have occurred and other relevant information

Photography—photos of scene and surroundings, mid-range to close-up photos with various angles of each piece of evidence, photos as viewed by any witnesses.

Sketches—inclusion of date, time, scale, reference points, distance measurements, names of investigators, victims, suspects, and a legend (key)

Videography—allows narration (non-subjective) to be included

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Please Do Now

State 4 factors that determine how a crime scene is searched?

State 4 things that an investigator might be looking for at a crime scene.

Please list them in your composition book.

Photo:http://www.usatoday.com/news/health/2002-10-30-evidence-usat_x.htm

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CRIME SCENE SEARCH PATTERNS

How to conduct a crime scene search depends on

One person should supervise and coordinate the collection of evidence

1. Location of the scene2. Time of day / weather3. Type of crime4. Details concerning events

of the crime5. Number of people

available for the search6. Available equipment

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TYPES OF CRIME SCENE SEARCH PATTERNS

Line or strip method —best in large, outdoor scenes Grid method —basically a double-line search;

effective, but time-consuming Zone method —most effective in houses or buildings;

teams are assigned small zones for searching Wheel or ray method —best on small, circular crime

scenes Spiral method —may move inward or outward; best

used where there are no physical barriers

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VEHICLE SEARCHES

Hit-and-run cases Outside and undercarriage of car are examined

Look for cross-transfer of evidence between car and victim (blood, tissue, hair, fibers, fabric impressions, pain, broken glass,…)

Homicide, burglary, kidnapping All areas of the vehicle, inside and outside, are

searched