Physical trace evidence such as paint is commonly found at crime scenes like hit-and-run accidents or burglaries. Paint contains pigments that impart color, a binder that holds the pigments, and a solvent that disperses the components. Automotive paint systems typically involve an electrocoat primer, a primer surfacer, a basecoat containing color pigments, and a clear topcoat for protection and shine. Microscopic examination of multiple matching colored paint layers can help relate two paint samples to a common origin, though there is no set number of layers required to make this determination. Entomology uses knowledge of insect colonization of remains to estimate time of death, as blowflies are usually the first to lay eggs which

1. Physical “Trace” Evidence

2. Paint most frequently encountered in hit-and-run and burglary cases often paint is transferred from one surface to another

3. Paint composition pigments – impart color and opacity binder – provides support medium for pigments and additives solvent – disperses pigments, binder etc. when applied, solvent evaporates leaving the hard binder with pigments suspended in it

4. Paint automotive finishing system for steel electrocoat primer epoxy based resins electrocoated to provide corrosion resistance uniform in appearance and thickness usu. black or gray primer surfacer completely smoothes out and hides any seams or inperfections highly pigmented to “match” or hide contrast between primer and topcoat

5. Paint automotive finishing system for steel basecoat colorcoat integrity of this layer depends on its ability to resist weather, UV radiation, and acid rain clearcoat unpigmented – applied to improve gloss, durability and appearance

6. Paint microscopic examination color surface texture color layer sequence when paint specimens possess colored layers that match in number and sequence of colors, the examiner can begin to relate the paints to a common origin no accepted criterion for # of layers to conclude a common source

7. Entomology knowledge of insects used to estimate time of death after death, blowflies are the first to infest the body eggs laid in remains, hatch into maggots or fly larvae consume human organs and tissues ID specific insects and stage of development to estimate time of death

8. Entomology

9. Entomology determination affected by environmental factors geographic location climate weather conditions determination affected by condition of body wrapped vs. unwrapped material used