Basic Crime Scene Sketching Chapter 2 Thanks to Special Agent Thompson for helping Mrs. Warren put this together

Sketches Hand-made pictorial representation of conditions at a crime scene Helps to clarify investigative data Explains the relative position, appearance, and condition of physical things which may be material to the investigation Purpose of sketch is for reconstruction of crime scene

When do we sketch? Death scenes Serious personal injury Sex crimes Serious property damage Whenever necessary to convey the facts FBI always sketches

Sketches Supplement Photos Photographs Provide great detail Do not always show true and accurate relationships Cannot determine distances Sketches Eliminate unnecessary detail Show true and accurate relationships Determine distances

Secure the Scene Exclude everyone without an official function Approach scene carefully and systematically  Have a plan! Preserve the relationships of objects Do not alter the position of any object until photographed and recorded Position, location, or relationship to other items is often as important as the object itself Record through notes, photographs, and sketches

Materials Required Clipboard Pencil and ERASER Ruler Tape measures Compass

Reference Points Must be accurately described on sketch Must be relatively permanent (likely to still be there 10 years later Fixed points Door frames Room corners Outside Utility poles Manhole covers Building corners Can be created (iron stake)

Three sketch methods Baseline Used 90% of the time Establish a baseline (points A and B) and describe all evidence in relation to these points Typically use the back of the room, but can use other places (like the middle of the room) Show outline of the room, doorways, and all evidence Leave out things that are not relevant All measurements go on table, no measurements on sketch

Baseline example Item Baseline Distance from baseline A B N S E W A = NW corner B = NE corner A → B = 24 ft. Item Baseline Distance from baseline 1 = Casing #1 3 ft. 12 ft. 4” 2 = Gun 5 ft. 8” 7’ 2” 3 = Casing #2 6’ 4” 4 = Body 17’ 4” 10’ 6”

Three sketch methods Triangulation Quickest method when only have a few items Need two reference points Measure distance to item from each reference point Again, put data in a table, not on sketch itself

Triangulation Example S E W A = Base of door frame, west B = Base of door frame, east A B Item A B #1 12’ 2” 10’ 6”

Three sketch methods Rose Compass Used by FBI ERT members Best for outdoors Orient with a magnet compass so that 0° is aligned with north Only reference point is the center Triangulate to center Can use iron stake Item Degrees Distance 1 45 ° 32’ 6” 2 330 ° 28’ 7” 3 85 ° 42’ 1”

Important Considerations Write down all measurements Fill in all details on rough sketch while at the scene Do not sketch on the same paper as the notes Measurements must be accurate (within reason) Critical distances should be checked by two officers

Required Information On ALL sketches include in a title block: “NOT TO SCALE” Magnetic north Case number Date Location (address) Name of sketcher and any assistants

Clean Sketch Clean sketch is done with a ruler back in the office Typically still not drawn to scale Usually don’t use graph paper Retain rough sketch as notes