Barbara,
At first glance it would seem unlikely that no prints
would be contained on the "kidnapping" note. However,
if you consider all of the dynamics involved in the
deposition and development of latent prints, it is not
so hard to understand.
Depending upon the type of paper that is handled,
latent prints are most often readily deposited and
will remain quite stable for extended periods of time.
If I accurately recall, the note in the Ramsey case
was written on a sheet from a legal pad. (Is that
right? I haven't really followed the case very
intently). That type of paper usually results in the
deposition of latent prints and retention of them.
However, I have examined many, many paper items in
over 23 years and the simple fact is that just because
an item is handled, it doesn't mean prints are going
to be deposited or recovered.
Development processes that are used on paper basically
consist of spectral and chemical techniques. Spectral
development techniques involve the use of a forensic
light source, such as a laser, to detect inherent
fluorescence. There are some biological components of
natural fingerprint residue that will fluoresce under
excitation within the proper wave-length. Chemical
treatment of the surface suspected of containing
latent prints may also enhance the ability to
visualize prints by means of a light source. These
techniques are not always successful, however, because
they are dependent upon either residue components that
are inherent or that react to the chemical reagent.
Ninhydrin solution is a development technique that is
the "workhorse" of latent print development on porous
paper items. It forms a colored chemical reaction with
the amino acids contained in natural residue. The
ridge detail of the print becomes visible in a dark
purple color - called "Rhueman's Purple". There are
other chemical methods, such as DFO, Physical
Developer, and Iodine fuming (which is not as widely
used in the modern age) that may be applied to paper
specimens. These all react to different components of
natural latent print residue.
The problem with being able to develop and visualize
latent prints on any surface, including paper, is that
there are so many variable and dynamic factors
involving the deposition, stability, and development
of the prints. While your postulation that it seems
likely that someone involved in a horrendous crime
would be perspiring heavily, that is not always the
case. Again, the many variables involved make it truly
a chance prospect. The unique physiological processes
of the individual account for some of this problem. As
we get older, we tend to perspire less. Our eccrine
glands (sweat glands) and sebaceous glands (oil
glands) tend to secrete less. This is just a general
guideline, there are, of course, exceptions to the
rules.
I would tell you from experience that I have seen
items that I know positively were handled by someone
that bear no fingerprints. Of course, I have seen
items that were known to have been handled contain a
wealth of fingerprints. The prospect is truly by
"chance," and that's why latent prints are sometimes
also referred to as "chance impressions."
Another thing about latent prints on paper, is that
quite often we may be able to determine that the item
has been handled, sometimes extensively. We are able
to clearly see some ridge detail develop. Many times,
however, the prints do not develop to a degree
sufficient to allow for individualization or
exclusion. This primarily results from a lack of
perspiration on the subject's hands and fingers. The
ridge detail may be fragmented to the point that it
cannot be compared. The natural print residue may be
so diluted that sufficient perspiration (amino acids)
was not deposited to form a strong enough color
reaction and the print subsequently is too faint to
clearly see the detail. So, it may be that prints were
developed, but they were insufficient in their clarity
to allow conclusive determination of who they belonged
to.
Having said all of that, I don't know the particulars
of the examination that was or was not conducted on
the evidence in this case. Without having reviewed the
examiner's bench notes and actually having examined
the evidence myself, I cannot say what conclusions
should have been reached. It would not surprise me,
however, that no prints were developed or prints
having insufficient quality to allow individualization
were found on the paper. I see this phenomenon over
and over again in every day case work.
I hope this answers some of your questions. Perhaps it
only raises more.
Sincerely,
***** CLPE SCSA
