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Articles from The Science Of Fingerprints

The Whorl

Name Files

Death Notices

Desiccation And Charring

Ridge Counting

How To Take Inked Fingerprints


The Use Of The Fingerprint Camera

Chemical Development Of Latent Impressions

General Photography

Advanced Decomposition

If the case is one involving decomposition, the operator is confronted
with the problem of dealing with flesh which is rotted or putrefied.
The flesh may be soft or flabby and very fragile. If this is so, an
examination is made of the finger tips to see if the outer skin is
present. If the outer skin is present and intact, it may be possible,
using extreme care, to ink and print in the regular manner. Sometimes,
the outer skin, although present, will be too soft and fragile to ink
and roll in the regular way. In such cases, when the ridge detail is
discernible, the skin, if it is easily removed from the finger, or the
finger itself may be cut off at the second joint and placed in a 10-
to 15-percent solution of formaldehyde for approximately an hour to
harden it. Skin placed in a formaldehyde solution usually turns a
grayish white and becomes firm. However, it will be brittle and may
split if not handled carefully. The skin is placed in the solution
only until it hardens sufficiently, after which it is removed and
carefully wiped dry with a piece of cloth. Then the skin, placed over
the operator's own thumb or index finger and held in place by his
other hand, is inked and rolled as though the operator were printing
his own finger. If a legible print is not obtainable in this manner,
the operator should examine the underside of the skin.

In many instances, where the ridge detail on the outer surface has
been destroyed or is not discernible, the ridge detail is clearly
visible on the underside (fig. 394). If this is the case, the skin is
inverted (turned inside out) very carefully to prevent splitting or
breaking and then is inked and printed in the usual way. It must be
borne in mind, however, that when the underside of the skin is printed
the resulting impression will be in reverse color and position; that
is, the ink is actually adhering to what would be furrows of the
pattern when viewed from the proper or outer side. If it is deemed
inadvisable to try to invert or turn the skin inside out for fear of
damaging it, a photograph of the inner ridge detail is made and the
negative is printed to give an as is position photograph for proper
classification and comparison purposes. In order to secure good
photographs of the ridge detail it may be advisable to trim the skin,
flatten it out between two pieces of glass, and photograph it in that
position (fig. 395).

When the entire finger is placed in the solution during the hardening
process, the skin, in absorbing the formalin solution, may swell and
come loose from the finger. Should this occur, the skin must be
removed carefully and the procedure outlined above followed. If,
however, the skin still adheres to the finger and is not too wrinkled,
ink is applied and prints made. Should the skin be too wrinkled to
secure a satisfactory impression, consideration is given to the
injection of the tissue builder under the skin as previously
mentioned, in order to distend the pattern area. If successful, the
finger is inked and printed. This, of course, can be done only when
the skin is intact.

Should part of the skin be destroyed to the extent that tissue builder
cannot be injected effectively, while examination discloses that the
pattern area is present but wrinkled, cut off the entire pattern area
from the joint to the tip of the finger (fig. 396). Care must be
exercised to insure getting the complete fingerprint pattern as well
as cutting deep enough to avoid injury to the skin.

After excision, the flesh is carefully and meticulously removed from
the inside by scraping, cutting, and trimming until only the skin
remains, or until the specimen is so thin it can be flattened out to
remove most of the wrinkles. If the skin is fairly pliable, the
operator should attempt to place it over one of his own fingers and
try several prints. If the prints secured are not suitable, the piece
of skin (exert care to avoid breaking or splitting) is flattened out
between two pieces of glass and photographed (figs. 397, 398, 399).

[Illustration: 397. Inked print made from the finger of deceased
before treatment.]

[Illustration: 398. Inked print made after skin was removed and

[Illustration: 399. Photograph of ridge detail of skin flattened
between two pieces of glass.]

The foregoing outline covers the procedures followed in cases
involving decomposition in which the outer skin is still present. In
many instances of decomposition the outer skin has been destroyed or
is in such a condition as to be of no value. It must be emphasized
again that the second layer of skin possesses the same ridge detail as
the outer layer and this, though finer and less pronounced, is just as
effective for identification purposes.

If, from examination, it is apparent that the outer layer of skin is
missing and the second layer is intact, the finger should be cleansed,
dried, inked, and printed in the usual manner. If the specimen is
wrinkled but pliable it may be possible to inject tissue builder, as
previously mentioned, to round out the finger, then ink and print it.

Occasionally, some of the outer skin is still attached but is of no
value. This skin should be removed by carefully picking or prying it
off with a scalpel in such a manner as not to destroy or injure the
ridge detail of the second layer. After the outer fragments have been
removed, the second layer is cleaned, inked, and printed. In the event
the resultant impressions are not suitable for classification and
identification purposes, the most likely reason for it is that the
ridge detail is too fine to print even though there are few if any
wrinkles in it. If this is the case, the finger should be cut off at
the second joint and photographed. Should wrinkles which cannot be
removed by injecting tissue builder, and which also preclude the
taking of suitable photographs, be present, the pattern area is cut
off with a scalpel from the first joint to the tip. The flesh is then
cut and scraped out as previously described, until the specimen is
thin enough to flatten out between two pieces of glass which may be
held together by scotch tape. The skin is then photographed.

Occasionally, even after the flattening process it will be noted in
the ground glass of the camera that the skin may be seen plainly but
the ridge detail is very poor. This difficulty may be due to the poor
contrast of the ridges and furrows when using direct lighting. If so,
it can be overcome by scraping the skin to transparency and then
photographing it by transmitted light (i.e., passing light through the
skin). Sometimes, due to the condition of the skin, even though it is
tissue thin, it will not be transparent. This can be overcome by
soaking the skin in xylene for a few minutes and then photographing it
by transmitted light while it is still impregnated with the xylene. If
the substance dries too fast to permit proper photographing, the skin
should be photographed while immersed in the xylene. (See subtopic of
this chapter pertaining to general photography.) Of course, after
the skin has been photographed the negative should be printed to give
a reverse position so that the print will be comparable with inked
impressions on fingerprint cards.

Next: Desiccation And Charring

Previous: Problems And Practices In Fingerprinting The Dead

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