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Dactyloscopist

Dactyloscopist. Fingerprint expert. Evidence. 3 different kinds of fingerprints Latent Prints Patent Prints Plastic Prints. Latent Prints. A chance or accidental impression left by skin on a surface

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Dactyloscopist

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  1. Dactyloscopist Fingerprint expert

  2. Evidence • 3 different kinds of fingerprints • Latent Prints • Patent Prints • Plastic Prints

  3. Latent Prints • Achance or accidental impression left by skin on a surface • Chemical, Electronic, and physical processing techniques show visualization of the invisible print • Print comes comes from sweat, motor oil, blood, paint, ink… • Very valuable physical evidence

  4. Latent Print

  5. Patent Prints • Friction ridge impressions of unknown origins • Transfer from a foreign material on a finger onto a surface • Visible • Photographed rather than lifted • Ex: ink, dirt, blood…

  6. Patent Prints

  7. Plastic Prints • Friction ridge impression from • Finger • Palm • Toe • Foot Keeps the shape of the ridge detail Ex: melted candle wax, thick grease Visible and doesn’t need photography

  8. Plastic Prints

  9. Fingerprint Capture • The machine mainly determines the difference in the ridges and the valleys • Two kinds of readers • Solid-state fingerprint reader • Optical fingerprint reader

  10. Classifying fingerprints • 4 different kinds of fingerprints: • Arch • Loop • Whorl • Tented Arch

  11. Arch

  12. Loop

  13. Whorl

  14. Tented Arch

  15. Case Study: Conviction Through Enhanced Fingerprint Identification • In 1990 an unknown assailant sexually molested and fatally stabbed a young woman. The only evidence was a pillowcase, found next to the victims body. It had several blood stains, one stain showed some faint fingerprint ridge detail.

  16. Investigation • Pillowcase to the departments forensic unit for bloodstain pattern analysis • Stains were consistent with a knife blade • Fingerprint had enough ridge detail to go further into the investigation • Image enhancement developed likely suspects and the the DNA proved the fingerprint match was correct

  17. Interview • “What kind of educational background do you have to have in order to work as a fingerprint expert?” • “It depends, there are different levels. There is on the job training and job preparation training; NCIC National Crime Index Certification and International Association of Identification. The person with the least amount of experience has worked here for 7 years.”

  18. “What is a typical day like for you?” • “It depends, I examine fingerprints of individuals that are arrested and process their identification to check their previous arrest history. I also review the work of coworkers to make sure they make proper identifications.”

  19. “Are you a forensic specialist all the time or do you have a "day job"?” • “There are different shifts. There is a late unit and a temperate unit which is 24 hours. There are three 8 hour shifts each day. There is a shift from 4am to 3 pm.”

  20. Resources • http://images.google.com/imgres?imgurl=http://www.fdle.state.fl.us/CrimeLab/images/fingerprint • http://www.wilsonnc.org/userimages/image/00000023_image002.jpg • http://en.wikipedia.org/wiki/Fingerprint#Patent_prints • http://static.howstuffworks.com/gif/safecracking-keypad.jpg • http://people.pwf.cam.ac.uk/jw566/research/photex/application/images/finger1.jpg • http://www.crimeandclues.com/92dec001.htm

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