Casts and Impressions

Impressions Types: Patent: visible (2D) Latent: not visible to eye Plastic: 3-D, left in material Class or individual evidence

Dental Impressions Bite marks = individual evidence Dental patterns used to: Identify remains Identify suspects at crime scenes DNA profile from saliva

Shoe Impressions (Shoeprints) Size Weight (depth of impression) Shoe type (personality, lifestyle) Activity (running, walking) Unique features: debris, gait (walking habit), holes/cuts # people, movements at crime scene

Preserving Footprint Evidence Photographs Lifting latent impressions Luminol Dusting Electrostatic lifting and gel lifting Casts Plaster of Paris (mud) Dental stone (snow)

Footwear Database

Tire Evidence Link a suspect or victim to crime scene Reveal events that took place Types: Skid marks (braking suddenly) Yaw marks (skid sideways in curved path) Tire scrubs (during or after impact)

Tire Marks as Evidence Preservation: Examination: Photographs Measurements Examination: Type of tire and make/model of car How vehicle was driven

Casts Permanent impression of plastic prints left at a crime scene Use Plaster of Paris or Dental Stone