Fingerprinting in the Digital Age Catherine Myers Independent Research Advisor: Gary Hauptmann Forensic Analyst Baltimore County Crime Lab
What is a Fingerprint? Ridges and furrows developed by dermal papillae Sebaceous gland Ridges and furrows developed by dermal papillae Skin secretions Invisible deposits Latent vs. patent Eccrine sweat pore
History of Fingerprinting Evidence of fingerprint use in ancient civilizations Sir Edward Henry made first classification system First fingerprint bureau in 1901 Loop Whorl Arch
Crossover Core Bifurcation Ridge Ending Island Delta Pore
Collecting Fingerprint Evidence Method depends on surface in question Porous v. nonporous Light v. dark Dusting Fuming Chemical development
Dusting Methods Powder: used on metal, glass and wood Black or white Fluorescent Magnetic: used on more porous surfaces like paper
Cyanoacrylate Fuming Superglue placed in sealed container Heated to approx. 120o Fumes evaporate Cyanoacrylate adheres to solid deposits of fingerprint View under UV light or dye with colored stain
Ninhydrin Development Used on paper Paper is submersed in ninydrin, allowed to dry Evidence is placed in a warm, humid environment Ninhydrin reacts with amino acids in fingerprint residue to form Ruhemann’s purple
Fingerprints?
Digital Enhancement Digital prints not as detailed as silver-developed prints Adobe Photoshop Color balance Brightness Contrast “Dodging and Burning”
Evidence How to Ensure that Evidence is Admissible in Court “If this is a digital image, has it been enhanced or is this the original capture with no changes to it? If it’s been enhanced, I want you to show me what you did and tell me what your training is. And did you go out of your area of expertise to do this? (McRoberts)” Record of camera, lens, shutter speed, illumination, camera position, and distance and angle from an object Audit trail to document changes made
More Safeguards Original photograph should be saved separately Changes should be directly reproducible Chain of custody should be documented and preserved
All photos obtained from www.google.com/images Sources All photos obtained from www.google.com/images Berry, John, and David A Stoney. "History and Development of Fingerprinting."Advances in Fingerprint Technology. Ed. Henry C Lee and R E Gaensslen. 2nd ed. N.p.: CRC Press, 2001. 1-41. Lee, Henry C, and R E Gaensslen. "Methods of Latent Fingerprint Development." Advances in Fingerprint Technology. 2nd ed. N.p.: CRC Press, 2001. 105-176. McRoberts, Flynn, and Steve Mills. "Digitized Prints can Point Finger at the Innocent." Chicago Tribune 3 Jan. 2005. 19 Dec. 2006 <http://www.truthinjustice.org/digitized-prints.htm>. O'Connor, Tom. Fingerprints and Trace Evidence. 26 Dec. 2004. North Carolina Wesleyan College. 14 Nov. 2006 <http://faculty.ncwc.edu/toconnor/315/315lect05.htm>. Prabahakar, Salir, and Anil Jain. "Fingerprint Identification." Biometrics Research. Michigan State University. 2 Nov. 2006 <http://biometrics.cse.msu.edu/fingerprint.html>. Ramotowski, Robert S. "Composition of Latent Print Residue." Advances in Fingerprint Technology. Ed. Henry C Lee and R E Gaensslen. 2nd ed. N.p.: CRC Press, 2001. 63-04. Reis, George. Digital Image Integrity. 2004. Adobe. 19 Dec. 2006 <http://www.adobe.com/digitalimag/pdfs/digital_image_integrity.pdf>. Scientific Working Group on Imaging Technologies. Vers. 1.1. Feb. 2001. Florida Division of the International Association for Indentification. 19 Dec. 2006 <http://www.fdiai.org/images/SWGIT%20guidelines.pdf>.