Why Take Photographs At A Crime Scene? Photographs document the scene in a way people can understand. Photographs can be used to recreate the crime and to prove or disprove a suspect’s explanation. They can help a jury understand where and how the crime was committed. A picture is worth a thousand words.
To Be Admissible in Court Fair Not biased or prejudicial Must not appeal to the emotions of the jury Accurate Technically correct Form, Tone, Color and Scale
To Be Admissible in Court Relevant Of value to the court and jury in making decisions Chain of Custody must be maintained The photo must be identified Introduced in court by a person who is qualified to identify it
Elements of a Good, Technical Photograph Must be correctly exposed Have maximum depth of field Have an accurate perspective Be in sharp focus
Types of Photographs Establishing photographs depict an overall view of the scene, buildings, approach and escape routes, witnesses, etc. Medium-range photographs depict the relationship between objects, concentrates more on the immediate scene. Close-up photographs depict individual items of evidence.
Flash photography is often needed during the day. As seen in the photograph, the camera’s eye is fooled by the bright brickwork, while the evidence is in darkness.
Same photograph, but with a flash. Now the evidence can be seen.
Footwear Impression @ 90°
Front Edge Front Axle Side Rear Axle Rear Edge Diagonal Diagonal Edge Edge Rear Edge Edge Front Diagonal Diagonal Front Edge Front Axle Side Rear Axle Rear Edge These 20 Photos + 1 Photo Directly Down = 21 Photos 21 Point Method
Fingerprints Should be photographed before lifting Orientation shot to show location Consider using black & white film for greater contrast Macro or close-up lens Scale on the same plane must be used 90 degree shot Use a tripod
Fingerprints
Low Light Photography Issues We often need to photograph scenes in low light, the following is an overview. The CSI Effect means that Juries no longer rely on just your word. They want to see what you saw. Your ability to shoot in low light will depend on Ambient light Your photography equipment Lighting Equipment that you can supply DWI equipment, etc. Other resources available to you Fire Department lighting equipment, etc.
Photography of Bloodstains Take orientation photos to show location Take close-up photos to show detail Keep the camera 90° to the print L-shape ruler is preferred to get both width and length of stain Consider using a tripod
Photography of Bloodstains Use bounced lighting or diffused light. Oblique lighting works best when dealing with stains on fabric (very low angles). May need additional magnification A macro lens or the macro feature on the camera A step-up lens
Overview, midrange, close up
Photos of bloodstains
Bloodstains @ 90° To the Floor
Bloodstains @ 90° to Wall
Fingerprints Should be photographed before lifting Orientation shot to show location Consider using black & white photogpraphy for greater contrast Macro or close-up lens Scale on the same plane must be used 90 degree shot Use a tripod
Fingerprints
Impression Evidence Orientation Show where the impression is located in the overall crime scene. Lighting Block out the ambient light with an umbrella and use a strong light source at an oblique angle to show the best details. Close-up Use a scale on the same plane as the impression. Keep the camera 90° to the impression Consider using a tripod
Tire Impressions Photograph tire impressions in sections showing one circumference of the tire. Taking overlapping photographs, with a tape measure, parallel to the tire impression. Keep the camera 90° to the impression
Tire Impressions
Photographing the Tread Pattern
Tool marks & serial numbers Orientation photo Evidence at the scene Close-up photos Use a scale on the same plane as the evidence 90 degree photo Oblique light to create small shadows in the detail Use a tripod .
Serial Number
High speed photography/videography and its applications in forensic science.
High speed videography Introduction High-speed videography is simply the technique of recording an event at a high frame rate and playing the images back at a much slower rate, thus slowing down the event so you can actually see what’s happening.
Key features of high speed camera ⚫A Fast Sensor ⚫Shutter Speed ⚫Sensitivity ⚫Light
Application of high speed videography ⚫In Military-ballistics and wind tunnel examinations, etc. ⚫Manufacturing companies-packaging, assembly and production lines, machine troubleshooting. ⚫In Medical Industries- analyze water droplets, chemical injections, biomechanics, fluid dynamics, etc.
A means of obtaining information from aerial photographs Photogrammetry is…
From a PowerPoint presentation by Fred Welter of North West Geomatics Ltd . The Science
Has many uses Very economical as opposed to on site surveying From a PowerPoint presentation by Fred Welter of North West Geomatics Ltd . Photogrammetry