Crime Scene Processing Series CRIME SCENE DIAGRAMMING New

Crime Scene Processing Series CRIME SCENE DIAGRAMMING New Mexico State Police Criminal Investigations Section Crime Scene Team

Learning Objectives Understand the purpose for preparing a diagram n Identify the information that must appear on a diagram n Demonstrate knowledge and proficiency in various methods of incident scene diagram n

Why do a Crime Scene Diagram? n It establishes a permanent record of the scene Associates evidence with the scene n Supplements photographs n n Useful in orienting a person to the scene n n Witnesses can look at a diagram without being prejudiced…you can’t show witnesses photos Useful in Court Easily blown-up for presentation n Not prejudicial to the jury n

Why do a Diagram, cont. The draw back of photos is that they are a two- dimensional representation of a three dimensional object n Most photos distort the relationship of the photographed objects, causing items to appear closer or farther apart than they actually are n The sketch is a bird-eye view, which is hard to get with a camera n

Methods Grid (X/Y) Coordinates n Triangulation Coordinates n Polar Coordinates n Raw Measurements n

Grid Method The scene in divided into four quadrants n Each item is measured at right-angles from each axis n This is a great method because it is easy & efficient n

Y axis Grid (X/Y) Method X axis (origin) The grid can also be expressed as north, south, east, and west measurements

Grid (X/Y) Method

Baseline Method Place a single line, dividing the scene in half n Measure relative to the line n Alone the baseline n At a right-angle to the baseline n n Great for a diagram where you have no fixed reference points

Incident: Bone Scatter, Death Investigation Location: Chavez County, NM Date: 3/3/07 Drawn by: R. Mathews Not to Scale REF. PT. 1 N: 32 degrees 41. 292’ W: 105 degrees 13. 951’ skull Leg bone torso Leg bone N Arm bone Trees Dry stream bed Arm bone Ref. PT. 2 N: 32 degrees 41. 317’ N W: 105 degrees 14. 003’

Triangulation Method Straight line distance measured from two (2) reference points n The item of evidence will be at the intersection of the two (2) arcs n This is a very accurate method of measuring n

Triangulation Method

Polar Method n Straight line distance measured from a fixed reference point Measure the distance from the reference point to the item of evidence n Document the line’s azimuth from the fixed reference point to the item of evidence n This is the best method for determining elevations above/below a fixed reference point n

Polar Method North 12 ft @ 120 degrees 18 ft @ 100 degrees

Raw Measurements The physical dimensions of a room/area n You should do this on every diagram to complement the main method of measurement n Width of roads n Distance from the victim’s hand to the gun n Overall dimensions of a room n

Raw Measurements

Information added to a USGS Map

Sketching the Crime Scene n Equipment n Measuring tapes, rulers n Hammer, nails, shop clamps Laser range-finder n Graph paper and PENSILS (avoid using a pen) n GPS n Maps, blue-prints, aerial photos n Accident/crime scene templates n

Sketching the Crime Scene n Its usually prepared in one of two ways Bird’s-eye-view (straight down) n Elevation (cross section) n Try to maintain proportionality (scale) n Double-check your measurements to be sure that they are correct n n Especially important if calculations will later be used n Bloodstain pattern analysis n Accident reconstruction n Shooting scene reconstruction

Sketching the Crime Scene n n n Crime scene diagram is similar to diagramming an auto accident with injuries Use fixed reference points and reference lines Diagram the location of all evidence, including the body n n Diagram the location of the head and the feet if practical. . . otherwise, diagram the location of the center-ofmass If you start a diagram & need to leave, make sure you pass on the responsibility to another person

Rough Draft

Finished product

Sketching the Crime Scene n Use the rough-draft to make a finished (court admissible) product n Hand-drawn is fine if you are a good artist n Use black ink and good paper n Use a template n Computer generated sketches are preferable n Can be easily reproduced without loss of quality n Can be easily blown-up or added to n Power Point Maintain the original, rough sketch n It is discoverable-just like your other field notes

Things to put in the Legend n Specific location of the scene n n n n Address, GPS Coordinate, etc. Date/Time Case Number Preparer Scale (or scale disclaimer ) Compass Orientation (North Arrow) Evidence Numbers Measurements

Court room presentations

Court room presentations

Court room presentations

Court room presentations

Court room presentations

Questions?