Chapter 14 Firearms, Tool Marks, and Other Impressions

Other Impressions What does “other” include? Main concern The process Shoe, tire, or fabric impression Preservation of the impression or its reproduction for later examination in the crime lab 1st – must be photographed Include a scale Show all observable details Side lighting for illumination helps highlight ridge details Show position of impression relevant to crime scene

Other Impressions How to get the original impression If it’s on glass, paper, or floor tile; easily removed Similar to lifting a fingerprint Place lifting material over impression, use roller to eliminate air pockets, lift Electrostatic lifting device (Pathfinder) Film placed on top of dust print mark, pressed down, high-voltage electrode used to create static charge Dust sticks to mylar sheet

Other Impressions Lifting Impression in soft earth Use a Class 1 dental stone – gypsum or plaster of paris Make the paste and gently pour into impression Snow Impression Wax to use on impressions left in snow that would be destroyed w/ other methods

Other Impressions Test impression necessary to compare the charac of suspect item w/ evidence impression Value of impression as evidence depends on # of class & individual characteristics found Class characteristics – size, shape, design of tread INDIVIDUAL characteristics – wear, cuts, gouges, or other damage Need sufficient # of pts of comparison What do you compare? http://members. aol.com/varfee/ mastssite

Famous “other” impression Bite marks! Make a mold of suspects teeth/bit impression to compare to photo of bit marks from victim Most famous – Ted Bundy – it was main piece of physical evidence that helped convict him Forensic Odontologist