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. 430).
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.]
Unknown Subjects Jones' Drug Co. B&E 3-15-47
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.