Vehicular Locard's principle and patterned tire markings

Area of Science:

• Forensic Pathology
• Trace Evidence Analysis
• Vehicle Forensics

Background:

• A fatality occurred involving blunt craniocerebral trauma consistent with being run over by a vehicle.
• CCTV footage confirmed the victim was alone and fell prior to the incident.
• Distinctive black patterned markings were observed on the victim's face and head during autopsy.

Observation:

• Distinctive black, patterned skin markings resembling tire treads were observed on the victim's face and head.
• These markings correlated precisely with the tread pattern of a suspect vehicle identified by police.

Findings:

• The markings were superficial, caused by the transfer of oil, dirt, and rubber from the tire tread.
• This phenomenon exemplifies Locard's principle, where physical contact leaves a transferable trace.

Implications:

• Such tire track impressions can be critical in linking a vehicle to a fatal incident.
• The superficial nature of the trace necessitates immediate, careful photographic documentation at the scene to prevent evidence degradation during body handling or cleaning.