investigative photography and crime scene sketches

Investigative Photographyand

Crime Scene Sketches

Crime Scene Photography

• One of the FIRST investigative tasks!!!

• Types of cameras used:

35mm SLR

Video

Digital

Polaroid

Crime Scene Photography

• Advantages of photographs

Can be taken immediately

Can accurately depict crime scene

Creates interest

Supports testimony

• Disadvantages of photographs

Do not show actual distances

Can be distorted

Digital images can be altered

Advantages of Video Taping

• Increases Intoxication convictions - DUI

• Enhances officer integrity

• Provides officer safety

• Documents traffic violations

• Reduces court time for officers

• Lowers liability for misconduct claims

• Documents probable cause and evidence

Disadvantages of Video Taping

• Records unwanted sound

• Documents errors made by officers and technicians

• Officers not always trained

• Discrepancies with Time/Date stamp

Types of Photographs

Establishing photographs depict an overall view of the scene, buildings, approach and escape routes, witnesses, etc.

Medium-range photographs depict the relationship between objects, concentrates more on the immediate scene.

Close-up photographs depict individual items of evidence.

This establishing photograph depicts the overall crime scene.

This medium-range photograph depicts the actual scene and relationship of evidence.

This close-up photograph depicts a single item of evidence.

Flash photography is often needed during the day. As seen in the photograph, the camera’s eye is fooled by the bright brickwork, while the evidence is in darkness.

Same photograph, but with a flash. Now the evidence can be seen.

Photographs should contain rulers or objects to help establish the size of the evidence.

In this instance, the known length of the bill can be used as a scale to determine the length of the knife.

Macroscopic photographs depict details of objects, and are taken at extreme close range.

An essential documentation step in

crime scene processing protocol

Keys to CrimeScene sketch:

DimensionDistanceContent

Relationship among items of evidence

Record the exact location and relationship of evidence to surroundings.

Refresh the memory of the investigatorProvide permanent record of conditionsAssist prosecutor, judge and jury to

understand conditions at the crime scene

Help in questioning suspects and witnesses

The General Uses of Photography

• Crime scene documentation

• Surveillance of people and locations

• Mug shots

• Line-ups

• Laboratory examination of evidence

Crime Scene Sketches

Sketches are important supplements to photographs and crime scene reports. Sketches….

• Accurately portray physical facts

• Relate to the sequence of events

• Establish locations and relationships

• Provide an overall picture of the scene

• Are a permanent record of the scene

The rough sketch is drawn at the crime scene. It is not a finish product, although it does contain measurements and other data.

Crime Scene Sketches

The finished sketch is often drawn by a draftsman to show proper relationships and scales. The finished sketch is more presentable for court presentations.

Rough sketch need not be to scale but should be proportional showing accurate

measurements to the nearest ¼ inch of the exact placement of the evidence and victim

No changes should be made to rough sketch once you leave the scene

Legend or key should be on both rough and finished drawings

Objects in scene should be marked with letters

Evidence marked by a circled numberNorth indicated on both drawingsMust show all relevant materials

Rough sketch may be made in pencil but final sketch must be made in ink

Steps in Sketching the Crime Scene

1. Observe the scene and plan the sketch

2. Measure distances

3. Outline the area (area dimensions)

4. Locate and draw objects and evidence within the sketch

5. Record all details

6. Depict legend, title, scale and direction of North

On the final sketch:Omit measurement lines

Must include all items that were in the rough sketch; no additions, no deletions

Scale notation must be notedBest if made by same investigator that

made the rough sketchAll measurements should face the same

direction.

Final sketch continued:Arrow heads should touch measurement lines

All hidden objects should be indicated by dotted lines

No conclusions should be noted on the drawings

Objects located by triangulation or coordinate method when possible

A Rough sketch is done by the technician

recording the exact placement of evidence and

victim.

Accurate measurements to two fixed points must be recorded so that a

scaled final sketch can be prepared for court presentation.

What are good examples of fixed

points?

A

10’8’

Triangulation Method of Locating Evidence

Item A is 10’ from the SE corner of the room, and 8’ from the SW corner of the room. These measurements will ALWAYS intersect at item A’s location.

A

Triangulation Method of Locating Evidence

Evidence must be triangulated to two fixed points. Not using the corners of the room, how would object A be triangulated?

desk

A

Triangulation Method of Locating Evidence

First, the desk is not fixed, as it is not touching the wall and its location has not been determined. To fix the desk, do this:

desk

A

Triangulation Method of Locating Evidence

Now that the desk has been fixed, object A can be fixed from two fixed points from the desk, as such:

desk

3’

1”

A

Triangulation Method of Locating Evidence

Now that the desk has been fixed, object A can be fixed from two fixed points from the desk, as such:

desk

3’

1”6’

5’

A

Triangulation Method of Locating Evidence

In this scenario, the desk is flush against the wall. How would object A be triangulated?

desk

A

Triangulation Method of Locating Evidence

The flush side of the desk is already fixed. One measurement is required to place the desk along the wall. Object A is then triangulated as usual.

desk

3’

5’

6’

A

Triangulation Method of Locating Evidence

This desk is flush in the corner against both walls. How would object A be triangulated?

desk

A

Triangulation Method of Locating Evidence

Since two sides of the desk are already fixed, object A is triangulated as usual.

desk6’

5’

A

Triangulation Method of Locating Evidence

Once evidence is triangulated, it can become a fixed point to triangulate other items of evidence. In this case, object B.

desk6’

5’

B

2’2’

Rectangular-Coordinate Method

A

B

15’

10’6’

6’

N

E

S

W Body

Tree

Shed

Compass

40°

340°

Azimuth Method of Triangulation

Reverse azimuth:340°-180°=160°

160°

Reverse azimuth:40°+180°=220°

220°

Administrative Data

LEGENDA. VictimB. RevolverC. Shell CasingD. Blood Stain

TITLECase: 1234-2001Location: Payson Hall, Room 111Victim: State of New YorkOccurred: Oct 31, 2001, 2300Drawn by: Detective GilbertVerified by: Detective Marlowe

Not to ScaleNorth Or

¼” = 1 foot

Rules for Drawing Sketches

• Never measure through space

• “Rotating” items require measurements at opposite ends

• Oddly shaped items, such as puddles of liquids, are triangulated from center of mass

• Do not cross measurement lines

• Always have the sketch verified

10”

13”

Since the blood droplets are of no particular defined shape, they are triangulated to the “center of mass”

Projection Sketch

Rough sketch of out door crime scene

Is usually prepared for courtroom presentation.

Must be to scale i.e. ¼ in. = 1 ft.

Units used must be consistent i.e. make all measurements in

metric or in feet/inches do not combine.