FORENSIC SCIENCE

Crime Scene Analysis

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CRITICALTHINKING

When Mrs. Jackson came back from lunch, there were several messages on her desk. By changing each digit of the phone numbers to one of the three corresponding letters on the telephone buttons, can you determine from whom each message came?

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Answers to Critical Thinking

336-8478 dentist(222)686-8268 accountant774-6837 printer487-2263 husband247-5463 airline832-2437 teacher

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FACETS OF GUILT

Means--the ability of have committed the crimeMotive--the reason for committing the crime.

(This doesn’t have to be proven or presented in a court of law, but its what everyone wants to know.)

Opportunity--time or availability to have committed the crime.

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Murder Charges

1st Degree Murder--premeditated2nd Degree Murder--killed intentionally, but not

thought out as much ahead of timeVoluntary Manslaughter--usually involves

sudden passion (fear, rage, anger, terror)Involuntary Manslaughter (criminally negligent

homicide)--killed someone, but unintentionally

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Crime Scene Team

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

Team Members First Police Officer on the scene Field Evidence Technician Medical Examiner (if necessary)

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First Officerat the Scene

A Assess the crime scene

D Detain the witness

A Arrest the perpetrator

P Protect the crime scene

T Take notes

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Evidence Technician Record the crime scene

Photography Sketches Notes

Conduct a search for evidence Set up numbers at the pieces of

evidence Has the necessary equipment

ForcepsBags--paper and plasticEnvelopes Jars and Q-tips

Properly collect all evidence Maintain a chain of custody Obtain reference samples (evidence

whose origin is known) Submit evidence to Lab

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Medical Examiner’sResponsibilities (Review)

Identify the deceased Establish the time and date of death Determine a medical cause of death--the injury or disease that resulted in

the person dying

Determine the mechanism of death--the physiological reason that the person died

Classify the manner of death Natural Accidental Suicide Homicide Undetermined

Notify the next of kin

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Physical Evidence

All objects that can establish that a crime has been committed

Can potentially link a crime to a victim and/or a crime to a perpetrator

Can be anything from massive objects to microscopic traces

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Evidence Characteristics

Class Evidence--common to a group of objects or persons

Individual Evidence--can be identified with a particular person or source.

ABO Blood Typing Blood DNA Typing

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Crime SceneSketch

Date: August 14, 2001 Criminalist: Ann WilsonTime: 11:35 Location: 4358 Rockledge Dr

St. Louis, Mo.

A. Couch/sofa

B. Female body

C. Knife

D. Over turned Lamp

E. Chairs

F. Table

G. Fireplace

cD

E

EE

E

E

A G

F

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Crime SceneSearch Patterns

Spiral Grid

TWO of FOUR PATTERNS

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Crime SceneSearch Patterns

Strip or Line Quadrant or Zone

TWO of FOUR PATTERNS

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Crime Scene Mapping(outdoors)

Azimuth--uses a compass beam to determine the location of each piece of evidence

Triangulation--uses two points at the crime scene to map each piece of evidence

Coordinate or grid--divides the crime scene into squares for mapping.

Suspended Polar Coordinate--for use in mapping evidence in a hole

Baseline--set a north/south line and measures each piece of evidence from this line.

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AZIMUTHDetermines:

•Direction•Distance•Elevation

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TRIANGULATION

Measure from A to B and then to the evidence in a triangular shape.

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Coordinate or Grid Mapping

Set a north/south line from a datum point established by a GPS. Make it a perfect square (4 x

4) by shooting the hypotenuse and setting in stakes every foot or meter.

Measure and map the location of each piece of evidence. Then collect evidence and place in containers by grid.

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Baseline Mapping

Set a north/south line from the furthest most points of the crime scene. Then measure each piece of evidence from that baseline. Evidence will need a numerical measurement where the piece begins, ends and in the middle.

Evidence Baseline

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Suspended Polar Coordinate

Measure and map each layer of evidence as you move down the hole. Use the compass readings from the top to measure degrees and a tank dipping line to measure depth.

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MAPPING TECHNOLOGY

The latest technology includes this Nikon Tsunami with computer. The exact location of all crime evidence can be determined and directly loaded into a computer to produce a crime scene map. Cost = $35,000 for the set.

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Remember:

“HOW PLUS WHY EQUALS WHO”--John Douglas, former FBI profiler

Keep this in mind as you analyze a crime scene…