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Unidentified Latent Fingerprint File

From time to time the FBI is requested to conduct surveys and

participate in conferences and in police schools on the problem of

fingerprint identification.

As a result of its observations in the course of these activities it

has been found that many identification bureaus are not fully aware of

the importance which latent finger impressions can have in connection

with the ordinary handling of arrest fing
rprint cards.

Many bureaus and departments spend considerable time in developing

latent impressions in a particular case. If no immediate results are

forthcoming, the latent impressions are filed for future reference.

Single fingerprint files have been maintained with success by some

departments. Many others do not attempt to keep a file because of

either limited personnel or lack of funds. In many departments,

however, where such a file is maintained, too often latent impressions

are simply filed with no regard to possible future use. Actually,

these impressions should be treated as evidence directly connecting

the subject with the crime.

Active consideration should be given to the latent impressions until

they are identified or the case has been successfully prosecuted. It

is definitely felt that the following suggested procedure might have

some decided advantages.

It is suggested that in all cases where latent impressions are

developed at the crime scene, or on an object used in connection with

the commission of a crime, the impressions be properly photographed

and lifted. The evidence, where possible and practicable, should be

properly packed, labeled, and stored for future use in court (fig.


Use care in wrapping the evidence to see that the latent impressions

on the objects are not destroyed. If the specimens are later used in

court, the impressions should still be clearly visible. In the same

manner, all evidence not of a bulky nature, such as photographic

negatives, photographs, and lifts of latent impressions, should be

similarly preserved for future court use. It is to be emphasized that

all material in one case should bear a case number. All specimens not

of a bulky nature can be placed in an envelope and filed by this case

number (fig. 431).

The above procedure is the usual one followed by the majority of

identification bureaus in handling latent impressions. In order,

however, to keep the latents in an active state, the photographs of

all the latent impressions found in a particular case should be cut up

and pasted on a 3 by 5 card bearing the case number and title of the

case (fig. 432).

[Illustration: 430. Evidence labeled and latents protected for storing

for future court use.]

[Illustration: 431. Latent material in a case should be filed under a

single case number.]

If numerous latents are developed, several cards should be used, all

having the same number and title. These cards are then filed by case

number in a regular filing cabinet. Before this step is taken, every

effort should be made to secure and compare the fingerprints of

individuals who may legitimately have placed their prints on the

objects which were examined. In addition, as part of the case report

bearing the same case number as the latent impressions, there should

be a notation pointing out that latent impressions were developed in

the case and that they are on file.

[Illustration: 432. For ready current comparisons latents in a case

are placed on a 3 x 5 card bearing case title and number.]

Case #2345

Unknown Subjects

Jones' Drug Co.



Fingerprint comparisons in this unidentified file can be made on the

basis of fingerprints taken from day to day of individuals

fingerprinted for criminal identification purposes. A routine may be

set up whereby the fingerprints of individuals arrested each day will

be compared the following day with the latent fingerprints filed in

the unidentified latent file. It is most important that this procedure

be rigidly followed from day to day. It is to be borne in mind that

the comparisons are made whether the particular person is or is not a

suspect in a certain case. Special attention should be paid to

fingerprints of individuals charged with burglary, breaking and

entering, armed robbery, and other similar crimes.

Should an identification be made of some latent prints, and others in

the same case remain unidentified, the 3 by 5 card should remain in

file until the case is fully closed, inasmuch as more than one person

may be involved in the crime. Of course, if all the latents are

identified, then the 3 by 5 card is removed and placed with the

negatives, lifts, etc.

It may be deemed advisable to remove these latents from the file in

instances where the statute of limitations covering the crime has run.

If the above procedure is rigidly followed, identification in many

instances will result--more than would be effected if the department

maintained only a single fingerprint file in which the latent prints

were merely filed away. Very often such a latent fingerprint file is a

source of information when all logical investigative leads have been


This resume of latent impressions has been prepared by the

Federal Bureau of Investigation in the belief that it may be

of possible interest to law enforcement officers desiring to

avail themselves of latent identification evidence in

connection with their investigative activities. It should be

borne in mind that the comments and expressions set out in

this book are not intended to convey the thought that the

Federal Bureau of Investigation believes the points

emphasized are the only ones of moment, or that other

methods of developing latent impressions are not equally

acceptable. The Federal Bureau of Investigation will be glad

to answer any questions on the foregoing which may occur to

any law enforcement officer who reads this material.