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					                          SKETCHING CRIME SCENES
1. Sketch, diagram, and drawing are terms used interchangeably to refer to a
handmade pictorial representation of conditions at a crime scene.
2. One court defined a diagram-as follows:
"A diagram is simply an illustrative outline of a tract of land, or something else
capable of linear projection, which is not necessarily intended to be perfectly
correct and accurate:"
"At best (diagram) is an approximation; and in this sense it is indifferent by
whom it is made. A witness may as well speak by a diagram and linear
description, when the thing nay be so described, as by words. It is enough if it
serves the purpose of the witness in the explanation of the lines and localities he
is seeking to exhibit."
NOTE: In this case the court held the diagram to be admissible even though it had
been made by the prosecuting attorney rather than by the witness in connection
with whose testimony it was introduced.
"The use of maps, models, diagrams and photo graphs as testimony to the
objects represented rests fundamentally on the theory that they are the pictorial
communication of a witness who uses this 1 method of communication instead of
or in addition to; some other method. It follows' then, that the map or
photograph must first, to be admissible, be made a part of some qualified
person's testimony. Someone must stand forth as its sponsor. In other words, it
must be verified.
"There is nothing uncommon or exceptional in this principle. It is the same
principle as required of all witnesses. The witness must have had observation of
the data in question, properly recollect these data, and then correctly express
these data. The diagram, map or photograph will not stand alone. There must be
a witness who has competent knowledge and who can affirm or swear that the
map, diagram or photograph represented the facts. This principle is borne out by
all the cases on the subject.
Above only applies to diagrams, maps, etc., used by the witness. Official maps of
state and county officers., etc.. are submitted under a different rule. Verification
or authentication may be enough in such cases. In our case the witness standing
sponsor for the map or drawing must be qualified by observation to speak of the
matters represented in the picture. Whether this requirement is fulfilled should
be left to the determination of the trial court
1. Must be made part of some qualified person's testimony.
2. Must have competent knowledge.
a. Dust have an observation of the data in question.
b. Must properly recollect these data
c. Must correctly express these data.
3. In other words, the sketch must be sponsored or verified.
4. In this connection, note that McKelvey states:
"...value ... is .. dependent upon its being a correct representation of the
original, and verbal
testimony must ... be offered .... that it is a correct representation of what it
purports to be"
A. Record the exact location and relationship of pieces of evidence and
B. Refresh the memory of the investigator.
C. Provide permanent record of conditions otherwise not easily recorded.
1. Distances involved in large areas
2. Topography
3. Paths of vehicles in accidents
4. Movement of suspect
5. Skid Marks
D. Assist prosecutor, judge, and jury to understand the conditions at the crime
E. Help in questioning suspects and witnesses.
F. Plan raids and roadblocks
G. Record details of accident investigations.
H. Help correlate testimony of witnesses.
I. Portray statistics graphically. (Refers to charts--not sketches)
J. Eliminate unnecessary and confusing details.
K. Organize forces for disaster and riot control -also special events.
Sketches Supplement Photographs
1. Purpose of each is to present a picture - to portray something.
2. Photograph gives great detail.
3. Sketch eliminates unnecessary detail.
4. Photograph provides permanent record of items that may be overlooked or
5. Photograph does not always show true and accurate relationships between
objects as to distance,
position, etc.
a. Cannot determine distances in a photograph.
b. Position of camera, tilt, type of lens, exposure, distance from object, etc.,
photographic proportions.
6. Frequently possible to show only a part of a scene in a photograph
7. Sketches combine features of both notes and pictures. In character they lie
between word
descriptions and photographs.
9. Notes, photographs, and sketches are always needed
Sketches Provide Reference or Orientation Points to Clarify Oral Testimony
1. Such words as "long," "far," "small," "in back of," "brown," etc., need a
point of reference or comparison.
2. In the sentence, "This is a small automobile:' the word "automobile" provides
the reference point.
3. Descriptions must be understandable to be useful. Reference points must be
4. Crime scene sketches often provide the needed reference points and avoid
much confusion,
Protect the Crime Scene
1. Exclude everyone who does not have an official function to perform, including
the residents,
relatives, and even officers.
2. Approach scene carefully and systematically.
a. Have a well-organized plan
b. Establish chain of command
c. Make definite assignments.
3. Preserve relationship of objects.
a. Do not alter the position of any object until it has been properly recorded.
b. The position, location, or relationship to other things is often as important as
the object itself.
c. Positions and relationships may be recorded through notes, photographs, or
Obtain Comprehensive View of Scene
1. Get over-all picture in mind.
2. Decide whether to make, sketch.
a. Is a sketch needed?
b. Who will use it?
c. For what purpose?
3. Decide what kind of sketch will best serve the purpose.
Types of Sketches
1. Floor plan or "bird's-eye view." This is the simplest and the most common
2. Elevation drawing. This type of sketch portrays a vertical plane rather than a
horizontal plane like a
plan such as described above.
3. Exploded view. This is somewhat of a combination of the first two types. It is
similar to a floor plan
except that the walls have been laid out flat and objects on them have been
shown in their relative
positions. Bullet holes, bloodstains, etc. , on walls can be shown in this manner.
4. Perspective drawings. Drawings of this type require more artistic skill. They
are difficult to draw to scale.
5. Most of the time the first type, the floor plan, will serve our purposes best.
Determine Sketch Limits.
1. Decide what to include and what may be excluded.
2. Choose fixed base line or fixed points for outdoor sketches.
Don't Rely on Memory.
Write down all measurements. Fill in all details on rough sketch while at scene.
Use Separate Paper.
1. Do not make sketch on same paper with notes.
2. Separate sheet will then be available in case someone else prepares finished
1. Supply of pencils - medium or hard lead.
2. Blank paper - graph paper, while not essential, is very helpful.
a. It simplifies scale drawing
b. It provides guide lines and automatic line measures.
c. Various kinds available having 4, 8, 16, 12, or 10 lines per inch.
3. Drawing surface - it is helpful to have a clip board.
4. Tape measure - should be at least 50, preferably 100 feet, and made of metal
or metallic cloth.
5. Folding rule - The 6-foot carpenter's rule is more convenient than the tape for
short measurements.
6. Ruler - Used for drawing straight lines, drawing to scale; and making very
short measurements.
7. Magnetic compass - or some means of determining true north, if unknown.
1. As a first step, the sketcher usually makes a very rough outline while
obtaining his over-all view of the scene.
2. Initial rough outline serves as a guide while making more complete rough
sketch (made at scene as compared to finished sketch made back at office).
3. Next step is to begin taking measurements and laying out sketch.
a. Lay down a base. Longest uninterrupted side of room. for example, if indoors;
curb line,
building line, bank of stream or even imaginary line between two fixed points if
b. Take other measurements of periphery of scene and add them to base line,
paying attention to proper angular and directional relationships. Having thus
established outer boundaries now proceed to add various objects in their proper
Measurements (WRITE THEM DOWN)
1. Must be accurate - within reason.
2. Don't be overly precise. To say that the top of the victim's head was 14"9 & 13
32nds inches from a telephone pole is overdoing it.
3. Long distances. such as a quarter mile or a half mile, may be measured with
the odometer on an automobile.
4. Critical measurements. such as the length of skid marks, should be checked by
two officers.
1. Area being sketched must be reduced to fit on paper.
2. Measurements must be reduced in proportion so that they bear correct
relationship to each other
otherwise the users of the sketch will get a distorted view of the scene. This is
what is meant by drawing to scale.
3. Scale is the proportion between the length of the lines in the drawing and that
which they represent.
4. Select scale by fitting longest dimension in crime scene to convenient area on
paper being used.
Example: Suppose your paper is a standard 8 x 101/2" sheet and the longest
measurement in your crime scene is 221/2 _. Obviously, you cannot use 1" to 1'
for your scale as that would require at least 221/2" of paper. Nor can you use
1/2" to 1' because then you would need 11/4" paper. The next most convenient
unit would be 1/4" equals 1'. This will make the longest dimension of the
drawing on your paper 5 5/8" (221/2 x 1/4 = 5 5/8), which would fit nicely on
your paper. You could use 3/8" to 1' and your drawing would then be almost
81/2" long, but 3/8" is not a convenient unit because it does not
divide evenly into 1" making fractions of a foot very awkward to calculate.
5. Use largest scale possible.
Example: Assume you-are using 8 x 101/2" paper for outdoor scene in which the
longest dimension is 190'. You can use a scale in which 1/2" equals 10'. In this
case, your drawing would be 19 half-inches (190 divided by 10) or 91/2" long
which will fit the paper nicely. This size is easier to see and to work
-with than the next smaller convenient scale which would be 1/4" equals 10'
because then the drawing would be only 4 3/4" long.
6. Use convenient units for scale.
7.In selecting scale bear in mind that the actual sketch on the finished drawing
should not take up the entire paper. There should be room left for the title and
the explanatory legend or key.
Locating Points on Sketch
1. All dimensions require 2 fix points and plot sketch.
2. Rectangular coordinates method
a. This is a simple system in which a point is located by making a measurement
at right angles from each of two walls: To locate point A, measure from the north
wall and from the west wall thus setting up an imaginary rectangle.
b. This system works well for rectangular or square rooms and inside
measurements generally.
c. You must be sure that the measurements are made at right angles from the
3. Straight line measurement
a. These measurements are used for recording location of objects in the crime
scene area.
b. Measurements are taken from fixed points to either side of the object.
4. Coordinates constructed on transecting base line.
a. Transect crime scene by laying down tape at some convenient point so it
crosses entire area as from A to B
b. Measure distance C and record.
c. Now objects within the crime scene can be located or plotted by measuring
their distance from this established base line (the.. tape).
d. Distances from the west wall to points a, b, and c are automatically read from
the tape which is now your base line.
e. Distances from points 1, 2, and 3 to your base line are measured at-right
angles to the tape.
f. This system is particularly useful in large, irregularly shaped outdoor areas
where no satisfactory natural base line exists.
g. System could be used in major disasters such as airplane crashes on farm
land, desert, etc. to show location of property, bodies, parts of plane, etc.
5. Triangulation
a. In this system, a measurement is made of two fixed objects to the point you
plot or locate so as to form an imaginary.
b. System is simple and accurate.
c. Can be used indoors or outdoors.
d. Especially good for areas lacking straight lines.
Dimension Lines
1. Should be faint lines with arrowheads.
2. Put each one in on rough sketch.
3. Keep finished sketch as free as possible of teem. This keeps from cluttering up
the diagram with extra and unnecessary lines; makes understanding easier. If
testimony is needed as to some measurement, you can refer to your notes or the
rough sketch. Any critical or important measurements may be shown if desired.
Techniques of Illustration
1. Do not try to draw objects to look as they would in a photograph.
2. Use standard symbols in sketching when possible. (Some standard symbols
are shown on the last two pages of this lecture note guide.)
3. You may use lettered or numbered squares, rectangles, circles or other figures
or even points for various objects and explain in the key what .they are.
4. Use heavy lines for building walls, outdoor boundaries, etc., for clarity and
5. Label all doors and windows clearly.
6. Show with curved line which way door swings.
7. Show with arrow the direction of stairway.
Labeling Objects
1. Use letter to label furniture and fixed articles.
2. Use number to label items of evidence.
3. Identify both in key.
1. Title should be set out in a block at some convenient place on the sketch. If
possible, put it at the lower right.
2. Following items should appear in the title:
a. Brief descriptive statement - John Doe's Apartment.
b. Address or location
c. Type of case
d. Date sketch made
e. By whom sketch was made
1. Show direction of north with an arrow. By convention, north is usually shown
at the top of the paper, if possible.
2. Show the scale. (Frequently included in the title block)
3. Try to approximately center drawing on paper.
4. Enlarged sections may be made as separate drawings in order to bring out
greater detail.
5. Unnecessary height or length may be cut off with jagged lines.
6. Check finished drawing for clarity, accuracy, scale, title, key.

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