crime scene processing series crime scene diagramming new mexico state police
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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 Identify the information that must appear on a diagram - PowerPoint PPT PresentationTRANSCRIPT
Crime Scene Processing SeriesCrime Scene Processing Series
CRIME SCENE CRIME SCENE DIAGRAMMINGDIAGRAMMING
New Mexico State PoliceNew Mexico State PoliceCriminal Investigations SectionCriminal Investigations Section
Crime Scene TeamCrime Scene Team
Learning ObjectivesLearning Objectives
Understand the purpose for Understand the purpose for preparing a diagrampreparing a diagram
Identify the information that must Identify the information that must appear on a diagramappear on a diagram
Demonstrate knowledge and Demonstrate knowledge and proficiency in various methods of proficiency in various methods of incident scene diagramincident scene diagram
Why do a Crime Scene Why do a Crime Scene Diagram?Diagram?
It establishes a permanent record of the It establishes a permanent record of the scenescene Associates evidence with the sceneAssociates evidence with the scene Supplements photographsSupplements photographs
Useful in orienting a person to the sceneUseful in orienting a person to the scene Witnesses can look at a diagram without Witnesses can look at a diagram without
being prejudiced…you can’t show witnesses being prejudiced…you can’t show witnesses photosphotos
Useful in CourtUseful in Court Easily blown-up for presentationEasily blown-up for presentation Not prejudicial to the juryNot prejudicial to the jury
Why do a Diagram, cont.Why do a Diagram, cont.
The draw back of photos is that that The draw back of photos is that that they are a two- dimensional they are a two- dimensional representation of a three representation of a three dimensional objectdimensional object
Most photos distort the relationship Most photos distort the relationship of the photographed objects, causing of the photographed objects, causing items to appear closer or farther items to appear closer or farther apart than they actually areapart than they actually are
The sketch is a bird-eye view, which The sketch is a bird-eye view, which is hard to get with a camerais hard to get with a camera
MethodsMethods
Grid (X/Y) CoordinatesGrid (X/Y) Coordinates Triangulation CoordinatesTriangulation Coordinates Polar CoordinatesPolar Coordinates Raw MeasurementsRaw Measurements
Grid MethodGrid Method
The scene in divided into four The scene in divided into four quadrantsquadrants
Each item is measured at right-Each item is measured at right-angles from each axisangles from each axis
This is a great method because it is This is a great method because it is easy & efficienteasy & efficient
Grid (X/Y) MethodGrid (X/Y) Method
X axis
Y a
xis
(origin)
The grid can also be expressed as north, south, east, and west measurements
Grid (X/Y) MethodGrid (X/Y) Method
Baseline MethodBaseline Method
Place a single line, dividing the Place a single line, dividing the scene in halfscene in half
Measure relative to the lineMeasure relative to the line Alone the baselineAlone the baseline At a right-angle to the baselineAt a right-angle to the baseline
Great for a diagram where you have Great for a diagram where you have no fixed reference pointsno fixed reference points
Incident: Bone Scatter, Death InvestigationLocation: Chavez County, NMDate: 3/3/07
Drawn by: R. MathewsNot to Scale
N
Trees
Dry stream bed
skull
Leg bone
Leg bone
torso
Arm bone
Arm bone
REF. PT. 1N: 32 degrees 41.292’W: 105 degrees 13.951’
N
Ref. PT. 2N: 32 degrees 41.317’W: 105 degrees 14.003’
Triangulation MethodTriangulation Method
Straight line distance measured Straight line distance measured from two (2) reference pointsfrom two (2) reference points
The item of evidence will be at the The item of evidence will be at the intersection of the intersection of intersection of the intersection of the two (2) arcsthe two (2) arcs
This is a very accurate method of This is a very accurate method of measuring measuring
Triangulation MethodTriangulation Method
Polar MethodPolar Method
Straight line distance measured from Straight line distance measured from a fixed reference pointa fixed reference point Measure the distance from the reference Measure the distance from the reference
point to the item of evidencepoint to the item of evidence Document the line’s azimuth from the Document the line’s azimuth from the
fixed reference point to the item of fixed reference point to the item of evidenceevidence
This is the best method for determining This is the best method for determining elevations above/below a fixed reference elevations above/below a fixed reference pointpoint
Polar MethodPolar Method
12 ft @ 120 degrees 18 ft @ 100
degrees
North
Raw MeasurementsRaw Measurements
The physical dimensions of a The physical dimensions of a room/arearoom/area
You should do this on every diagram You should do this on every diagram to complement the main method of to complement the main method of measurementmeasurement Width of roadsWidth of roads Distance from the victim’s hand to the Distance from the victim’s hand to the
gungun Overall dimensions of a roomOverall dimensions of a room
Raw MeasurementsRaw Measurements
Information added to a Information added to a USGS MapUSGS Map
Sketching the Crime Sketching the Crime SceneScene
EquipmentEquipment Measuring tapes, rulersMeasuring tapes, rulers
Hammer, nails, shop clampsHammer, nails, shop clamps Laser range-finderLaser range-finder Graph paper and PENSILS (avoid using a Graph paper and PENSILS (avoid using a
pen)pen) GPSGPS Maps, blue-prints, aerial photosMaps, blue-prints, aerial photos Accident/crime scene templatesAccident/crime scene templates
Sketching the Crime Sketching the Crime SceneScene
Its usually prepared in one of two waysIts usually prepared in one of two ways Bird’s-eye-view (straight down)Bird’s-eye-view (straight down) Elevation (cross section)Elevation (cross section)
Try to maintain proportionality (scale)Try to maintain proportionality (scale) Double-check your measurements to be Double-check your measurements to be
sure that they are correctsure that they are correct Especially important if calculations will later Especially important if calculations will later
be usedbe used Bloodstain pattern analysisBloodstain pattern analysis Accident reconstructionAccident reconstruction Shooting scene reconstructionShooting scene reconstruction
Sketching the Crime Sketching the Crime SceneScene
Crime scene diagram is similar to Crime scene diagram is similar to diagramming an auto accident with injuriesdiagramming an auto accident with injuries
Use fixed reference points and reference Use fixed reference points and reference lineslines
Diagram the location of all evidence, Diagram the location of all evidence, including the bodyincluding the body Diagram the location of the head and the feet if Diagram the location of the head and the feet if
practical...otherwise, diagram the location of the practical...otherwise, diagram the location of the center-of-masscenter-of-mass
If you start a diagram & need to leave, make If you start a diagram & need to leave, make sure you pass on the responsibility to another sure you pass on the responsibility to another personperson
Rough DraftRough Draft
Finished productFinished product
Sketching the Crime Sketching the Crime SceneScene
Use the rough-draft to make a finished Use the rough-draft to make a finished (court admissible) product(court admissible) product Hand-drawn is fine if you are a good artistHand-drawn is fine if you are a good artist
Use black ink and good paperUse black ink and good paper Use a templateUse a template
Computer generated sketches are preferableComputer generated sketches are preferable Can be easily reproduced without loss of qualityCan be easily reproduced without loss of quality Can be easily blown-up or added to Can be easily blown-up or added to Power PointPower Point
Maintain the original, rough sketchMaintain the original, rough sketch It is discoverable-just like your other field It is discoverable-just like your other field
notesnotes
Things to put in the Things to put in the LegendLegend
Specific location of the sceneSpecific location of the scene Address, GPS Coordinate, etc.Address, GPS Coordinate, etc.
Date/Time Date/Time Case Number Case Number Preparer Preparer Scale (or scale disclaimer )Scale (or scale disclaimer ) Compass Orientation (North Arrow)Compass Orientation (North Arrow) Evidence NumbersEvidence Numbers Measurements Measurements
Court room Court room presentationspresentations
Court room presentationsCourt room presentations
Court room Court room presentationspresentations
Court room Court room presentationspresentations
Court room Court room presentationspresentations
Questions?Questions?