Evening star., 1933-05-28
CRIMINALS Barred
BY INVISIBLE CLUES
Latest Fingerprint Methods
Described in Bureau of
Identification Bulletin.
BY REX COLLIER.

How the modern scientific detective
armed with dragons blood powder, ul-
tra-violet ray apparatus or other de-
vices, Is able to discover latent finger
print clues, invisible to the naked eye, is
explained by the United States Bureau
of Investigation in its "Fugitives Want
ed" bulletin, distributed to 5000 law
enforcement agencies.
While no mention is made of specific
cases. 1t is of interest to note that such
methods were used in the Lndbergh
kidnanins case to reveal hidden finger
prints Of the Lindbergh baby on toys,
furniture and other articles in the
child's nursery These prints were taken
secretly and held with view to clinch-
ing identification of the missing baby
in the event it was found. The condi-
ton Of the infants body made finger
print comparisons impossible, however.
Much Success Achieved
The Bureau of Investigation has had
notable success in solving number OF
major crimes through development Of
latent fingerprints. Perhaps the out
standing case Of this kind was the La
mar, Colo. bank robbery and quad
ruple murder crime Of few years ago,
In which single fingerprint smudge
cent men from execution and trapped
the guilty fugitives.
The bureau describes latent prints as
''those markings, usually rather indis-
tinct, left by oily matter or perspira-
ton exuded from the flngertipS upon
any substance which the fingers may
touch"
Authorities differ as to the time latent
prints will remain upon any object
touched. it is pointed out. Atmospheric
conditions may affect them slightly, it
is said, but the physical condition of
the person leaving the latent impress
sions, considered with the surface to
which the prints are adherlng, will al
feet their duration considerably"
"It is sufficient to state that they re-
main intelligible and readily susceptible
Of development for several days where
they. are placed under ideal conditions"
the bulletin states. For example, If
they appear upon piece of glass. steel
or other hard surface non-porous ma
terial, it is usually possible to develop
them, through the application of the
proper materials or substances, several
days after they are so placed"
"Peeling of" Method.
While the usual method Of preserv-
ing fngerprints is to develop them with
powders and then photograph them,
there have been cases where the prints
literally were lifted from the surface
to which they had adhered by use of a
process akin to the well known decalo-
mania system. This "peeling-of
method is not so satisfactory as the
Photographic process, however, and is
employed only where conditions are un-
favorable to photography.
The Department Of Justice generally
develops latent prints with a white or
gray powder, consisting of finely ground
chalk and mercury, or with a black
powder of lampb!ack or charcoal. It
also has made use of dragons blood
powder (f1nely ground resin of the rat
tan palm tree), aluminium and bronze
powders. Sometimes iodine fumes are
necessary to disclose faint impressions
on paper and ultraviolet light also
brings out otherwise invisible prints
The powders may be blown on the print
with an atomizer, brushed on with
cannels hair or, as in the case of a
piece Of paper, spread on by tapping.
Clue on Auto Door.
In the Lamar bank murders powder
applied to door Of an automobile
abandoned by the fugitives disclosed a
partly obscured print Of one finger A
photograph Of the print was forwarded
to the Bureau Of Investigations identi-
fcation division here. Months later a
nngerprint examiner who had memo
rized peculiarities of the print recog-
nized one exactly like it that had been
sent in by police who had arrested a
man in another city. This man eventu-
ally confessed that he and his brother
had participated in the Lamar crime
Among important latent prints still
held as possible clues in unsolved crimes
in the files of the Justice Bureau is a
palm print obtained from the automo-
bile in which Mary Baker, Navy De-
partment clerk, was murdered on April
II, 1880. This case, like the Lindbergh
kidnapping and other unsolyed mys-
teries, will remain officially open"
until definitely cleared up.