Latent print on car door handle

[AmyC]

Can anyone point me to any recent literature on prints left in a high traffic area, such as a door handle? Is there any support for the proposition that the last person to touch a door handle was likely the last person to use that door because they would disrupt any prior prints? Thanks!

[Michele]

Personally, I think this is more of a logic problem than a research issue. Here’s my logic (feel free to poke holes in it, I always like to know where my logic is faulty).
From some known facts we can make generalizations for specific situations.

Fact 1: The time that an item was touched cannot be determined (however, it may be able to be estimated in some situations).
Fact 2: Latent prints, made from sweat, are fragile and easily destroyed.

If there were a latent print on an item
and then the latent print were touched,
then the portion of the latent print that was touched will likely be destroyed.
This is in regard to touching the latent print itself, not necessarily the item.

If an item is large then someone may touch the item in a place that may not be touched by others and could remain on the item for years (lots of case examples of this). However, if the item is small then there are less places to touch the item, meaning that every touch will likely be close to other touches. In some cases, the touch could in the exact same spot (the trigger of a gun, the spot on my car where I touch to lock the door, a door bell).

Therefore, there is a correlation between the size of an item and how likely the latent is to be disturb (or destroyed). As the size of an item gets smaller, the likelihood that the latent print found being from someone who recently touched the item increases.

An additional element to consider is the matrix of the latent print reside. If the matrix is sweat, as stated above, then it is fragile. However, if the matrix is some sticky substance that has dried, maybe residue from a lollypop, then a latent print may not be so fragile and not as easy to obliterate.

If I don’t know the matrix then I personally would not speculate too much. I’d rather just give this information and let others (attorney’s and jurors) speculate for themselves.

Hope that helps.