FIELD FORENSIC TECHNIQUES

1. FIELD FORENSIC TECHNIQUES

2. Wildlife Crime Scene Management, Processing and Reconstruction

3. FIRST ON SCENE • Self Security • Handle any medical emergencies • Call for additional help if necessary • Follow these three steps • 1)Management • Processing • Reconstruction

4. MANAGEMENT OF CRIME SCENE • IS SEARCH WARRANT NEEDED? • ESTABLISH SCENE LIMITS • REVIEW SCENE CONTAMINATION OR ALTERATIONS THAT MAY HAVE ALREADY OCCURRED • REVIEW EVIDENCE ALREADY COLLECTED • INITIAL WALK THROUGH TO DETERMINE SCOPE OF THE SCENE

5. ASSIGN ROLES AND DUTIES (SECURITY, ENTRY LOGS, DOCUMENTATION, PROCESSING, COLLECTING, PACKAGING, EVIDENCE SECURITY) • FINAL WALK THROUGH • MAINTAIN AND COORDINATE WITH OTHER PARTS OF THE INVESTIGATION

6. PROCESSING A CRIME SCENE • LOCATION AND ID PHYSICAL EVIDENCE • DOCUMENT THE SCENE (PHOTOGRAPHS) • COLLECT AND PACKAGE EVIDENCE • CLOSE THE SCENE (EXIT PHOTOS)-CONFER WITH TEAM MEMBERS AND AGREE ALL EVIDENCE HAS BEEN RECOVERED

7. TYPES OF EVIDENCE • BIOLOGICAL (BLOOD, HAIR) • PHYSICAL (SHELL CASINGS, PHOTOS, GUNS) • TRACKS (ANIMAL, SHOE PRINT, TIRE PRINT) • GEOLOGICAL (SOIL SAMPLES) • ENTOMOLOGY SAMPLES (INSECTS) • ELECTRONIC (COMPUTERS, CELL PHONES)

8. DETERMINING TIME OF DEATH IN WILDLIFE • WHY DO WE NEED TO DETERMINE TIME OF DEATH? • HOW DO WE DETERMINE TIME OF DEATH?

9. ITEMS EXAMINED TO DETERMINE TIME OF DEATH • TEMPERATURE • ELECTRICAL STIMULUS • RIGOR MORTIS • PHYSICAL CHANGES IN THE EYE • CHEMICAL CHANGES IN THE EYE • INSCETS

10. TEMPERATURE • After death, the body temperature approaches ambient temperature through loss of heat by radiation, convection and conduction.

11. Cooling Rate • Initial body temperature • Air temperature • Body surface area and weight • Handling of carcass after death • Fairly similar for given spp

12. Initial Body Temperature • Deer have an average body temperature of 102 degrees

13. Ambient Temperature • Air temperature • Estimate daily temperature by averaging temperature readings at dawn and 3 pm or the previous 12 hours

14. Determining Body Surface and Weight • Use chart to determine body weight by measuring girth of chest. • One chart for live weight • One chart for dressed weight • Difference in buck and doe and fawn (shown on chart)

15. LOCATIONS TO TAKE TEMPERATURE • CENTER OF DEEP MUSCLE (THIGH OF THE HIND QUARTER) • NASO-PHARYNGEAL CAVITY

16. CONDITIONS THAT CAN AFFECT COOLING RATE • DELAYED DRESSING (LITTLE EFFECT ON HEAD BUT DELAYED THIGH TEMPS) • HEAD COOLS FASTER THAN BODY • CARCASS THAT WAS WASHED WITH COOL WATER • SKINNING • MOISTURE • WHERE IT IS STORED

17. DETERMINING TIME OF DEATH FROM TEMPERATURE READINGS • HAVE TO REFER TO CHARTS • CAN RUN COMPUTER AP TO DETERMINE • KEEP IN MIND THAT THIS IS USED IN CONJUNCTION WITH OTHER METHODS TO NARROW DOWN THE TIME. IT SHOULD NOT BE USED BY IT’S SELF

18. ELECTIRCAL STIMULUS • RESPONSE TO ELECTRICAL STIMULUS IS CHEMICALY RELATED TO THE AMOUNT OF ADENOSINE TRIPHOSPHATE (ATP) IN MUSCLES. • AFTER DEATH ATP BREAKS DOWN AND RESPONSE TO ELECTIRCAL STIMULUS DECREASES WITH TIME UNTIL NO REPSPONSE IS OBSERVED

19. FACTORS THAT DETERMINE RESPONSE • SEVERE DEATH STRUGGLE VS QUICK DEATH • STRESS • FATIGUE • BEST USED TO DETERMINE WITHIN 4 HOURS OF TOD • DIFFERENT MUSCLE GROUPS GIVE DIFFERENT RESPONSES

20. MUST RELY ON CHARTS FOR ESTIMATING TIME OF DEATH BASED ON RESPONSE TO DIFFERENT MUSCLE GROUPS.

21. RIGOR MORTIS • POST MOREM STATE OF RIGITITY WHICH DEVELOPES IN MUSCLE TISSUE WHEN ATP DEPLETES • DEPENDANT ON PHYSIOLOGICAL AND AMBIENT TEMPERATURE FACTORS • DIFFERENT JOINTS ARE AFFECTED AT DIFFERENT TIMES • MULTIPLE JOINTS NEED TO BE CHECKED

22. JOINTS TO CHECK • JAW • NECK • WRIST • ANKLE • ELBOW • KNEE

23. STATE OF RIGOR • EACH JOINT SHOULD BE CHECKED AND THE STATE OF RIGOR NOTED • NONE • PARTIAL • FULL

24. DETERMINING TIME OF DEATH USING RIGOR • REFER TO CHARTS

25. TOD BY PHYSICAL CHANGES IN THE EYES • FOLLOWING DEATH, EYE APPEARANCE CHANGES FROM RIGOR MORTIS OF THE IRIS MUSCLE AND FROM THE LOSS OF TRANSPARENCY AND VOLUME OF THE INTER OCULAR FLUIDS • RIGOR MORTIS OF THE IRIS MUSCLES CAUSES PUPIL CONSTRICTION (CAN BE MEASURED WITH DIVIDERS OR CALIPERS)

26. MEASUREMENT OF EYES • USE EYE WITH GREATEST PUPIL CONSTRICTION • MEASURE PUPIL DIAMETER VERTICALLY AT RIGHT ANGLES TO THE LONGEST LATERAL DIAMETER • LATERAL DIAMETER REMAINS CONSTANT • VERTICLE DIAMETER DECREASES WITH TIME • USE CHART TO DETERMINE TOD

27. ESTIMATING TOD FROM EYE COLOR CHANGES • FIRST HALF HOUR AFTER DEATH-EYE LENSE AND FLUIDS FULLY TRANSPARENT • 30 MINUTES TO 6 HOURS AFTER DEATH- LENS AND FLUID REMAIN TRANSPARENT, LUMINOSITY AND COLOR MAY DECREASE SLIGHTLY • 6 HOURS TO 10 HOURS- COLOR CHANGES TOWARD GREY

28. 12 HOURS TO 18 HOURS- COLOR FADES TO DULL GREY, LUMINOSITY FADES AWAY, PUPIL NARROWS TO 1/3 OR LESS OF ORIGINAL DIAMETER • AFTER 30 HOURS- COLOR AND PUPIL DIAMETER REMAINS THE SAME. HAZY BLUE COLOR APPEARS OVER BROWN COLOR AFTER 48 HOURS

29. CHEMICAL CHANGES IN THE EYES • MEASURE POST MORTUM GLUCOSE LEVELS IN THE EYES (NOT AVAILABLE IN FIELD) MUST BE SENT TO LAB AND NOT VERY ECONOMICAL • WE DON’T USE THIS IN THE FIELD