Yoelit Migron, 1 Ph.D.; Gil Hocherman; 2 Eliot Springer, 2 Joseph Almog, 2 Ph.D.; and Daniel Mandler, 1 Ph.D. Visualization of Sebaceous Fingerprints on Fired Cartridge Cases: A Laboratory Study REFERENCE: Migron Y, Hocherman G, Springer E, Almog J, Cantu (5) confirmed that fingerprints on fired cartridge cases gave Mandler D. Visualization of sebaceous fingerprints on fired car- poor results when developed by superglue vaporization with or tridge cases: a laboratory study. J Forensic Sci 1998;43(3):543–548. without electroless multimetal deposition (gold deposition fol- lowed by silver). However, they argued that diluted ‘‘gunblue’’ ABSTRACT: The visualization and endurance of fingerprints on solutions gave good results on both fresh and old fingerprints on cartridge cases after the firing process have been examined. Car- brass, nickel and washed copper-fired cartridge cases. Donche tridges of M16, AK-47 (Kalashnikov) and Parabellum have been tested. Despite difficulties in visualizing these fingerprints, it was reported that superglue developed fingerprints on fired plastic and found that in some cartridge cases under laboratory conditions—for cardboard cartridge cases but worked poorly with fingerprints on instance, on M16 brass cartridges—substantial parts of the finger- fired metal (brass, nickeled brass, and lacquered steel) cartridge prints remain intact after shooting. The careful use of illumination cases (13). Similarly, electroless multimetal deposition of gold fol- after metal vapor deposition enabled visualization. Different possi- ble mechanisms responsible for the partial destruction of the finger- lowed by silver gave positive results with smooth plastic cartridge prints are discussed. cases and negative results with metal cartridge cases (13). On the other hand. Given (14) claimed that black powder and vapors of KEYWORDS: forensic science, latent fingerprints, fired cartridge HNO 3 developed good images of the fingerprints on both brass cases and nickeled brass cases, even 21 days after printing and firing. Very recently Brown and his co-workers (15) claimed that vacuum cyanoacrylate (with fluorescent staining) and selenous acid treat- Latent fingerprints visualized on fired cartridge cases, which are ments were the most suitable method for visualizing fingerprints imprinted before the firing process, serve as excellent forensic on spent cartridge cases; however, only certain revolvers and the evidence in criminal and terrorism cases. However, visualization SLR rifle yielded identifiable ridge details. In brief, all these reports of such fingerprints is still not always successful using current allude to the difficulty in visualizing fingerprints on fired cartridge techniques. Moreover, the endurance of such fingerprints has been cases. questioned for many years. In this report we demonstrate that in many cases, substantial Several methods of visualizing latent fingerprints on pristine parts of fingerprints on M16 brass cartridge cases survive firing, brass cartridge cases have been developed. Metal exchange reac- under laboratory conditions, and stay partially intact. They are tions (by immersion plating), copper-selenide (CuSe) deposition, optically visible and can be better visualized after vapor-deposited black powdering, and cyanoacrylate polymerization produce good coating with reflecting metals which improve their visibility. An images of latent fingerprints on unfired cartridge cases (1–7). explanation of the changes that the fingerprints undergo upon firing However, the results obtained by these methods upon treating fired is suggested based on these results. cartridge cases are often not clear and reproducible. Research in the Israeli Police laboratories and other forensic laboratories showed that an ammoniacal solution of silver nitrate and Experimental ‘‘gunblue’’ solution visualized latent fingerprints on unfired car- tridge cases, but gave poor results on fired cartridge cases (4,5). Chemicals Used Plasma etching revealed good images of unfired fingerprints, but gave only very partial images of fingerprints on expended car- Palladium dichloride and dipotassium hexachloropalladate were tridges (8). A combined procedure of polymerization with purchased from Aldrich. Black (1-001 Black) and magnetic pow- superglue (9,10) followed by plasma etching also failed to developders were received from Lightning Powder Co. (Salem, OR) good images on fired cartridge cases (11). Sampson reported that whereas ‘‘gunblue’’ solutions (Kettner Waffen Bru ¨nierung Nr. superglue developed latent fingerprints on fired nickel cartridge 40099) were purchased from Kettner (Germany). The brass 5.56 cases, but not on fired brass cartridge cases (12). Saunders and mm caliber unfired cartridges for the M16 were produced by the Israel Military Industries (IMI). 1 Department of Inorganic and Analytical Chemistry, The Hebrew Uni- versity of Jerusalem, Jerusalem 91904, Israel. Visualizing Instruments 2 Division of Identification and Forensic Science, Israel National Police Headquarters, Jerusalem 91906, Israel. Preliminary routine observations of the latent fingerprints and Received 3 July 1997; and in revised form 20 Oct. 1997; accepted 20 Oct. 1997. the developed images were made with a magnifying glass ( 2 5) 543