FBI logo...

This booklet concerning the study of fingerprints has been prepared by the Federal Bureau of Investigation for the use of interested law enforcement officers and agencies, particularly those which may be contemplating the inauguration of fingerprint identification files. It is based on many years' experience in fingerprint identification work out of which has developed the largest collection of classified fingerprints in the world. Inasmuch as this publication may serve as a general reference on

  The FBI Identification Division was established in 1924 when the records of the National Bureau of Criminal Investigation and the Leavenworth Penitentiary Bureau were consolidated in Washington, D.C. The original collection of only 810,000 fingerprint cards has expanded into many millions. The establishment of the FBI Identification Division resulted from the fact that police officials of the Nation saw the need for a centralized pooling of all fingerprint cards and all arrest records. The Fed

  Fingerprints may be resolved into three large general groups of patterns, each group bearing the same general characteristics or family resemblance. The patterns may be further divided into sub-groups by means of the smaller differences existing between the patterns in the same general group. These divisions are as follows: Illustrations 1 to 10 are examples of the various types of fingerprint patterns.   Figs. 1-2 Figs. 3-8 Figs. 9-10 [Figs. 1-10] Before pattern definition can be understood,

  No matter how definite fingerprint rules and pattern definitions are made, there will always be patterns concerning which there is doubt as to the classification they should be given. The primary reason for this is the fact that probably no two fingerprints will ever appear which are exactly alike. Other reasons are differences in the degree of judgment and interpretation of the individual classifying fingerprints, the difference in the amount of pressure used by the person taking the prints,

  At this point it is necessary to mention that when prints are classified, markings are indicated at the bottom of each finger block to reflect the type. The following symbols are used: ● Under the index fingers the appropriate capital letters should be placed for every pattern except the ulnar loop. ● Under all other fingers, the appropriate small letter should be placed for every pattern except the ulnar loop and the whorl as follows: ● Ulnar loops in any finger are designated by a diagonal l

  Emphasis should be placed upon the necessity for fully referencing all scarred patterns. In connection with their proper classification, the following rules should be observed: ● When an impression is so scarred that neither the general type of pattern nor the ridge tracing or count can be determined with reasonable accuracy, the impression should be given both the general type value and the subclassification value of the corresponding finger of the other hand. ● When an impression is partiall

  The sequence must be arranged properly at all times to make possible the most accurate work. Prints are sequenced and filed in this order, according to: I. Primary: In the primary classification the denominator remains constant until all numerator figures have been exhausted from 1 to 32. All prints with the primary 1 over 1 are filed together. These are followed by 2 over 1, 3 over 1, 4 over 1, etc., until 32 over 1 is reached. The next primary is 1 over 2, then 2 over 2, etc., until 32 over

  When searching a print through the fingerprint files in order to establish an identification, it should be remembered that the fingerprint cards are filed in such a way that all those prints having the same classification are together. Thus, the print being searched is compared only with the groups having a comparable classification, rather than with the whole file. After locating the proper group classification, the searcher should fix in his mind the one or two most outstanding characteristi

  The equipment required for taking fingerprints consists of an inking plate, a cardholder, printer's ink (heavy black paste), and a roller. This equipment is simple and inexpensive. In order to obtain clear, distinct fingerprints, it is necessary to spread the printer's ink in a thin even coating on a small inking plate. A roller similar to that used by printers in making galley proofs is best adapted for use as a spreader. Its size is a matter determined by individual needs and preferences; ho

  From time to time various problems arise concerning the taking of inked impressions. It is believed that these problems can be divided into four phases: ● Mechanical operation ● Temporary disabilities ● Permanent disabilities ● General In order to take good fingerprints, the necessary equipment should be maintained in a neat and orderly manner at all times. Poor impressions are usually caused by one of the following faults: 1. The use of poor, thin, or colored ink, resulting in impressions whi

  Each year new graves are opened in potter's fields all over the United States. Into many of them are placed the unknown dead—those who have lived anonymously or who, through accident or otherwise, lose their lives under such circumstances that identification seems impossible. In a majority of such cases, after the burial of the body, no single item or clue remains to effect subsequent identification. As a result, active investigation usually ceases and the cases are forgotten, unless, of cours

  For the information and assistance of officials who desire to establish a local fingerprint identification bureau, the following suggestions are being made to indicate the principal materials necessary to equip such a bureau: For the purpose of taking fingerprints there should be a stand with a clamp for holding the fingerprint cards steady. This latter item is necessary to prevent smudging the prints. A tube of printer's ink is used. The ink is applied by a roller to a glass plate upon which

  Each ridge of the fingers, palms, and soles bears a row of sweat pores which in the average person constantly exude perspiration. Also, the ridges of the fingers and palms are in intermittent contact with other parts of the body, such as the hair and face, and with various objects, which may leave a film of grease or moisture on the ridges. In touching an object, the film of moisture and/or grease may be transferred to the object, thus leaving an outline of the ridges of the fingers or palm th

  The sole purpose in "developing" a latent impression is to make it visible so that it may be preserved and compared. Various powders and chemicals are used for this purpose. When a latent print is plainly visible, it should be photographed before any effort is made to develop it. No attempt should be made to brush or apply powder to prints in dust, obviously greasy prints, or bloody prints, as this will almost surely destroy them. Objects which have been wet or immersed in water may still bear

  Chemical treatment in the development of latent finger impressions on paper, cardboard, and newly finished or unpainted wood may involve a slightly more complicated technique than that in which powders are utilized, but the results justify the additional effort. It is very strongly recommended that powders not be applied to articles of the above types. This recommendation is made for several reasons. First, powders cannot be removed from paper and possibly may interfere with some types of docu

  If a fingerprint is visible, an effort should be made to photograph it before any attempt is made to develop it. In every case a print developed with powder should be photographed before lifting. It sometimes happens that the print does not lift properly although it may be quite clear after development. The camera which is especially adapted to the purpose and which is easiest to handle and operate is the fingerprint camera, one type of which is shown in figure 424. This camera has several adv

  In testifying to fingerprint identification, the expert often prepares charts to visually aid the court and jury in understanding the nature of his testimony. Many times it is undoubtedly difficult for the layman to perceive, from a vocal explanation alone, the full import of an expert's testimony, due to its technical nature; consequently, some graphic representation of the facts presented is amply justified and rewarded. The preparation of the charts is ultimately the sole responsibility of

  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 fingerprint cards. Many bureaus and departments spend considerable time in developing latent i