| Author | Message | ||
     Laurie Joiner (Unregistered Guest) Unregistered guest Posted From: mailhost.polksheriff.org |
What methods are best used to process the interior of a vehicle where a fire was started, burned the seat, and burned itself out, due to lack of oxygen? | ||
| Elizabeth Howdle |
Iam intrested in this subject 'The Fire effect on fingerprints' as I am about to write about fingerprints recovered from a fire secen. Therefore, please if you have any infomations about the topic can you please send it to my e-mail | ||
| Wes Sossamon |
It is correct that the water contained within the eccrine residue is what evaporates under those conditions. It is also correct that those remaining constituents will react with certain development techniques under certain circumstances. However, it has been my experience that latent prints consisting solely of eccrine secretions are less stable under arid conditions than those involving sebaceous secretions. I do not suggest that latent print searches should not be conducted according to sequential processing methods under these conditions, nor should there be any erroneous expectation that none will be found. The stability of latent print residue is dependent upon many, many other variable factors beyond exposure to the ambient conditions to which it is exposed. I do not intend to imply that such latent prints cannot be visualized through appropriate development processes. I apologize for my failure to clearly state this in my response to the question. | ||
| N. Yubi |
Wes Sossamon wrote, "Higher temperatures, especially occuring in low humidity conditions, are found to have a more detrimental effect on eccrine secretion prints due to a rather rapid evaporation of the deposited residue." The deposited residue does not evaporate. The water evaporates. Eccrine gland secretions are roughly 98 to 99% water. The water evaporates, leaving behind the soluble amino acids, proteins, polypeptides, etc., which react well with latent print development procedures." | ||
| Wes Sossamon |
Exposure to elevated temperatures generally have a significant effect on latent print residue, mostly relevant to the visualization and recovery of the print. There are a plethora of variable factors that influence this, however. Exposure to very arid ambient conditions results in the marked effect upon the latent print. Exposure to relatively elevated temperatures in an environment with relatively high humidity, many times will result in the latent print residue remaining quite stable. These are general statements and there are cases that demonstrate the opposite to be true. As far as the ability of latent print constituents being able to survive the high temperatures of say, an arson fire, there are cases in which identifiable latent prints have been located and recovered at fire scenes. An analyst or examiner should always conduct a search for latent prints at a fire scene, just as with any other suspected or known crime scene. It is interesting that you would ask specifically about latent print constituents resulting from sebaceous secretions. It may generally be considered that latent print residue containing a relatively high concentration of sebaceous components will fare better than those consisting largely of eccrine secretions. Higher temperatures, especially occuring in low humidity conditions, are found to have a more detrimental effect on eccrine secretion prints due to a rather rapid evaporation of the desposited residue. Again, these are general statements and must be considered in the context of the individual case under examination. All of these variable conditions mentioned here, and many that are not, are part of the reason why it is virtually impossible, in reality, for an examiner to accurately estimate the "age" of a latent print based solely upon whether or not the print itself is easily visualized with high clarity of the detail or cannot be visualized subsequent to sequential processing. | ||
| Maryanne |
Exactly what effect do high temperatures, (those found in arson cases), have on the saturated fatty acids found in sebaceous fingerprints and on other constituents found in latent fingerprints? Thankyou. I would also like to thank Ed German for an extremely helpful reply to my last question. |
