Mr. Latona. When I received this exhibit, 626, the brown wrapper, it had been treated with black dusting powder, black fingerprint powder. There was nothing visible in the way of any latent prints on there at that particular time.
Mr. Eisenberg. Were you informed whether any fingerprints had been developed by means of the fingerprint powder?
Mr. Latona. No; I determined that by simply examining the wrapper at that particular time.
Mr. Eisenberg. Could you briefly describe the powder process?
Mr. Latona. The powdering process is merely the utilizing of a fingerprint powder which is applied to any particular surface for purposes of developing any latent prints which may be on such a surface.
Now, we use powder in the FBI only on objects which have a hard, smooth, nonabsorbent finish, such as glass, tile, various types of highly polished metals, and the like.
In the FBI we do not use powder on paper, cardboard, unfinished wood, or various types of cloth. The reason is that the materials are absorbent. Accordingly, when any finger which has on it perspiration or sweat comes in contact with an absorbent material, the print starts to become absorbed into the surface. Accordingly, when an effort is made to develop latent prints by the use of a powder, if the surface is dry, the powder will not adhere.
On the other hand, where the surface is a hard and smooth object, with a nonabsorbent material, the perspiration or sweat which may have some oil in it at that time may remain there as moisture. Accordingly, when the dry powder is brushed across it, the moisture in the print will retain the powder giving an outline of the impression itself.
These powders come in various colors. We utilize a black and a gray. The black powder is used on objects which are white or light to give a resulting contrast of a black print on a white background. We use the gray powder on objects which are black or dark in order to give you a resulting contrast of a white print on a dark or black background.
Mr. Eisenberg. Now, Mr. Latona, how did you proceed to conduct your examination for fingerprints on this object?