|Posted on Monday, April 30, 2001 - 12:23 pm: ||
Regarding cyanoacrylate fuming as a potential process on a nonporous surface that has been wet, it is generally not possible to know the chemical composition of latent print residue... especially for translucent or nearly invisible latent prints. Latent prints may include sebaceous gland (or other oily) contaminates which could survive water contact. Thus, cyanoacrylate fuming should normally be included among the procedures considered for nonporous surfaces (even those having been wet) AFTER photographing any visible identifiable friction ridge detail (you mentioned that ridge detail could be seen).
Cyanoacrylate fuming is similar to water condensation in some aspects (though not the exact same mechanism). Polymerization will occur uniformly on a surface that has had no disturbances (no touches, contact with contaminates, etc.). Think of a bathroom mirror fogging up when you shower: though appearing almost completely clean, many "wipes and swipes" from the last time you cleaned the mirror suddenly appear as the condensation occurs. Cyanoacrylate fuming will generally develop ridge detail present, regardless of whether it is natural eccrine gland secretions (which include, salts, amino acids, proteins and much more) or whether it is sebaceous gland or other "oily" contaminates which can and do survive contact with water.
Based on individual evidence/case circumstances and equipment/chemicals used by the agency, sometimes other procedures such as RUVIS, RTX, iodine fuming, SPR, etc., might also be considered when the evidence was known to have been wet.
|Posted on Sunday, April 29, 2001 - 05:40 am: ||
I was recently told by a fingerprint examiner when I had submitted articles, containing latent fingerprints that had been wet, for superglue fuming that the process would not work because the water would have washed away the salts present in the latent. Even though the ridge detail of the print could still be seen, ie the print could be seen but needed enhancing in order to photograph it, she was adament that it would not work. However my research of this topic has not given me this conclusion. Please could you tell me if the examiner is correct.