Posted on Sunday, December 12, 2004 - 10:22 am:

1 - In practical application, there is no valid scientific method to determine if a person's age has changed from one latent print deposit and a later one. The difficulty is on what caused the latent print to be deposited (see earlier discussions)and then what development technique is employed. In theory, there has been research conducted that shows a difference in the chemical makeup of perspiration, natural body oils, etc., that can 'make' latent prints (most notably amino acids), at different ages. More specifically, children versus adults. However, even that research is on significant aging of the individual, not something like six months. So, latents made with biological fluids may have differences, but the latent print substance has to be tested and analyzed before application of developing methods. The key here is the word, latent. Latent means hidden, invisible, so testing would be difficult if you did not know where the latent substance is located or what body fluids are present. Also, the difference may not be attributed to age, but environment and diet. This is just a brief and simple explanation. There are so many factors that would have to be considered to even attempt a valid scientific determination.

Ernie Hamm


2 - Because an expert CANNOT know what was on the finger (popcorn oil, Vitalis, natural secretions, etc.) it is impossible to venture a guess as to how old a latent print could be? The expert had better have ESP if he's going to "date" a latent print by conjecturing that it had to be from natural secretions from the suspect's fingers/palms and could not have been completely or partially a contaminated transfer.