Lecture 19 Tire Print Evidenc e

1. Lecture 19Tire Print Evidence Evidence Often Overlooked

2. Vehicle-Involved Scenes • Vehicle-involved scenes run the gamut of scene types: homicides, sexual assaults, burglaries, drive-by shootings, terrorist events, etc. • Identifying vehicle should be a critical aspect of any on-scene investigation. • In typical homicide investigation, investigators must consider the possibility that specific categories of physical evidence related to the crime are present. • Hit and run crimes, whether vehicle-vehicle, vehicle-person, vehicle-other object, involve vehicles that leave the scene. • In these crimes, damage creates physical evidence • Evidence could prove the culprit vehicle was at the scene; • This evidence should be collectable.

3. The following article from the New York Daily News is such an example[1]. In this case, the suspect and his vehicle were found. The NYPD crime scene unit had the responsibility of working the car to prove it was the vehicle that struck the victim.

4. Case Example Kidnapping • Hypothetical - Kidnapping • Involves a vehicle for transport • Critical to find physical evidence that the child had been inside the car, • Reality: Such evidence may not be present or had been removed. • The abducted child case. • No evidence found inside the suspect vehicle proving the child there … • Must consider other, indirect, avenues to move investigation forward. • The abductor vehicle had been at the scene. • Success includes thorough investigation of the outside where the vehicle might have been parked • Physical evidence collected and scene archived. • One example of physical evidence vehicles leave behind is tire track impressions.

5. Tire Track Impression Evidence • Evidence Often Overlooked • Footwear Impression: • Dealt with locating, enhancing, photographing, etc, footwear impression evidence, • Much of that discussion is applicable to tire track evidence as well. • Similarities with Footwear Impressions • Tire track evidence: • Classified as two-dimension (2D) or three-dimension (3D). • Commonly in dust or are otherwise contaminated 2D impressions or impressions in a soft surface. • Considered Class or individualizing: • Physical characteristics needed for meaningful criminalistic-quality comparisons • Former provides information about the tread design • Latter provides information imbedded into the tread of the tire from daily usage.

6. Footwear & Tire Track Differences Their Intrinsic Forensic Values • Provides evidence of the individual (shoe impressions) or the vehicle (tire impressions) being at the scene, • For tire tracks, suggests the individual vehicle was used in the crime. • Tire track impressions geared to identify vehicle … not the person, • Although the person might have been driving the vehicle.

7. How Important is Scene Evidence? • Identifying specific vehicle requires recovering it and making direct comparisons with physical evidence from scene • Scene data allows investigators and laboratory analysts to narrow the search among universe of vehicles. • Until suspect vehicle is located and impounded, all scene data must be archived, collected and preserved. • Determining which tire tracks to photograph, enhance and or cast is critical

8. Critical Vehicle InformationCrime Scene Procedures Direction of travel Relationship of impressions @ scene to arrangement of tires on suspect vehicle Position of front of vehicle Which impressions made by front & rear tires Which impressions to photo/cast Locations where vehicle track measurements will be recorded Other relevant evidence Footwear impressions Fluid spills • How vehicle was maneuvered? • Vehicle characteristics • Stance • Track measurements • Wheelbase • Tread wear indicators • Wear bars • No. vehicles & no. occupants • Were objects loaded or unloaded?

9. On-Scene Considerations

10. Success At the Scene One Shot at It • Unknown: • Whether something seemingly unimportant and ignored will be important as evidence AND suddenly plays a prominent role in the investigation. • Consider everything at vehicle-involved scenes as potentially probative. • Misperception that tire track impressions have little forensic or investigative value. • General scene investigative principles apply equally to vehicle-involved scenes; • Management, archiving, searching, etc, are an integral aspect of the investigation.

11. Crime Scene Procedures Secure the area Tire prints protected Obtain information Case information Vehicle information Scene information Establish safe path to view evidence Archive Collect/package/preserve evidence

12. Management • Should employ guidelines previously discussed • While these principles are inviolate • Unique characteristics for vehicle-involved scenes. • Specifically, identifying, archiving, characterizing and preserving the physical evidence associated with identifying a suspect vehicle. • Investigative Questions • Archiving • Sketching and critical on-scene measurements • Vehicle information • Suspect information • Reconstruction

13. Archiving

14. Archiving • Photographing, sketching, video, 3D-Imaging tire-track and other vehicle-involved scene evidence • Much like for footwear impression evidence. • For tire track impressions – Document at least 24” of impression • For comparison purposes

16. Considering Lighting and Glare3-D ImpressionBlocking Sunlight Using Ambient Light

17. Photographing 3-D Impressions Photograph before casting Reproduces class characteristics Accidental characteristics are often lost Spray paint may enhance sufficiently Outdoor lighting may make it necessary to block direct sunlight Sometimes sunlight may be superior to oblique lighting Use polarizing filters to eliminate glare Look for sidewall information in impression

18. Photography – Effect of Lighting • Existing light blocked out and oblique light provided with off camera Flash

19. Archiving 3D Impressions Casting http://projects.nfstc.org/ipes/presentations/Bodziak_Footwear-Non.pdf

20. Archiving 3D Impressions Casting

21. Tire Impressions in the SnowReverse Sidewall Impression

22. Marking Tire Impression EvidenceVehicles Still at the Scene Photographer’s name, Date, Time Use scales in plane of impression Mark tire position on vehicle & on scene Use spray fluorescent paint for all wheels Rt front, etc Arrow pointing to front of vehicle Establishes inside & outside edge of impression Impression number 1st or 6th impression recorded @ the scene N/S directional

23. SketchesTire Track Impressions • Plan sketches: Overview of impressions • In-Depth detail not important • Measurements • Photography

24. Archiving – Sketches Include Vehicle-Critical Measurements • Sufficiently detailed to permit a determination of specific vehicle characteristics • Dependent on the amount and detail of the tire track impressions present. • Appropriate measurements must be made. • The measurements are the critical data needed to compare the on-scene tracks with a suspect vehicle.