Policy Text
CATEGORY DATE ADOPTED LAST REVIEW NEXT REVIEW
4 01/24/2011 06/01/201 9 06/01/20 21
TUSTIN POLICE DEPARTMENT
STANDARD OPERATING PROCEDURES
SS110 - Crime Scene Sketching 1 SS110 CRIME SCENE DIAGRAMS
SS110.1 PURPOSE AND SCOPE
The purpose of this procedure is to describe the process for creating crime scene diagrams .
Diagrams clarify the appearance of the crime scene and make it easier to comprehend.
Diagrams and photographs complement each other to more accurately depict the crime scene.
There are two types of diagrams , hand -drawn and computer generated .
SS110.1.2 ACCREDI TATION STANDARDS
This procedure pertains to the following CALEA Standards: 83.2.1 ; 83.2.4
This p rocedure relates to the following General Orders: N/A
SS110.2 SKETCHES/DIAGRAMS
The photograph is ordinarily a two -dimensional representation of the crime scene and, as such,
does not provide accurate information concerning the distance between various point s in the
scene. The relationship that exists between objects in the scene cannot be clearly understood
unless the measured distances are known. A d rawing or crime scene sketch is the simplest and
most effective way of showing actual measurements and of identifying significant items of
evidence in their locations at the scene.
SS110.3 HAND -DRAWN SKETCH
a) The rough sketch is made by th e evidence tech on scene;
b) It need not be drawn to scale, but the proportions should be approximated and the
appropriate me asurements or dimensions shown;
c) The rough sketch may be used as a basis for the finished drawing.
SS110.4 ELEMENTS OF SKETCHING
a) Measurements
1. Measurements must be carefully taken but may be approximate ;
2. Measurements should be accomplished by the person creating the sketch while
his or her assist ant (scribe) verifies all readings ;
3. Measurements establishing the location of a movable object must be based on
an immovable object. While measurements may be indicated between movable
objects to establish a correlation , at least one set of dimensions must reach an
immovable object.
b) Compass Direction
CATEGORY DATE ADOPTED LAST REVIEW NEXT REVIEW
4 01/24/2011 06/01/201 9 06/01/20 21
TUSTIN POLICE DEPARTMENT
STANDARD OPERATING PROCEDURES
SS110 - Crime Scene Sketching 2 1. Compass direction must always be indicated to facilita te proper orientation of the
sketch ;
2. The compass is used to determine “North.” A standard arrow of orientation will
indicate this direction on the sketch.
c) Essential Items
1. The sketch should portray all items that have a bearing on the investigation being
conducted. The inclusion of unnecessary detail will result in a cluttered or
crowded sketch ;
2. Simplicity is essential and sketches should be limited to the inclusion of only
relevant material ;
3. Measurements will be made of the room and all objects. The distances will be
measured and recorded.
d) Scale or proportion
1. The scale of a drawing will normally be dependent upon the area to be portrayed,
the amount of detail to be shown, and the size of drawing paper available. It is
normally advisable to use the smallest scale practicable ;
2. If a rough sketch is made, the size of an object may be approximated as
correlated to other objects. For example, if one dimension of a room is thirty feet
and the other ten feet, the first line would be approximately three t imes the length
of the second.
e) Legend
1. The legend is the explanation of symbols used to identify objects in the sketch;
2. In sketches portraying a large area, conventional signs or symbols may be used.
These sh ould be explained in the legend;
3. If it is necessary to show considerable detail in a sketch covering a small area,
the various objects may be lettered and an explanation included in the legend.
f) Title
1. The title of a sketch should contain the case identification (case number and
offense); identifi cation of victim or scene portrayed; date and hour made; and the
person creating the sketch .
SS110.5 COMPUTER GENERATED DIAGRAMS
Computer generated diagrams should be completed by the evidence tech who made the rough
sketch at the scene. Sketches can be created using various software programs following the
same elements of sketches as stated above.