|Posted on Monday, October 07, 2002 - 09:39 pm: ||
Generally, powdering is one of the last in the sequential processing techniques and by powdering you would eliminate the possibility of "going back" to the first possible process. However, if we ignore that the items were powdered, then you should commence with visual and light source examination. RTX fuming is non invasive and will locate latents that may be contaminated with fats and oils etc. I would always prefer to VMD (after RTX) before CA. It is more sensitive than CA and can detect very old latents. CA is not so sensitive but it has been known to still work on some older latents. Depending on the glass color of the bottles and any advertising label, staining may not be required if these substrates are a dark color. If not try R6G in water as opposed to methanol as a staining agent and view at 514.5. This may be less harmful to any latent deposits if you still wish to progress to any other process after CA. General staining by way of GV/CV or Sudan Black may be another option. The integrity of the stored items may be of issue. While you may develop additional latents, are these of investigative/legal personnel that may have handled the items after the initial examination?
Terry A. Smith
|Posted on Thursday, September 19, 2002 - 12:08 pm: ||
Any thoughts on this cold case?
Beer bottles examined for fingerprints 20 years ago with conventional powdering. The resulting developed latents have all been photographed, compared, and several "idents made". We're looking at developing anything that the previous technique may have missed as we have at least one unidentified "person of interest". Our collective thoughts are CA>dye staining>VMD. By the way, the bottles had been stored in dry & dusty environment(s). Any thoughts would be appreciated, particularly if similar experiences are involved.