ACOS 2.2, 2.3 Print Classification Henry System- adopted in 1901, looked at ridge patterns on all 10 fingers, but only accommodated 100,000 sets of prints Primary Classification- divides all fingerprints in the world into 1024 categories – Turns patterns into fractions – 1/1 means that all of the fingers have the same patterns Approximately 25% of the population have 1/1 ratio

ACOS 2.2, 2.3 Uses of these systems 10 finger system is only of use when the investigator has the names of the suspects on hand Can be entered into a database and matched

ACOS 2.2, 2.3 AFIS Automated Fingerprint Identification System Computer database of all fingerprints in the country Monitored by the FBI Allows for electronic comparison of a latent print to a known print Helps to identify suspects Reality of AFIS…Deanna Rice

ACOS 2.2, 2.3 AFIS The computer’s search determines the degree of correlation between the location and the relationship of minutiae of both the search and file prints Prior to AFIS, police had to compare prints by hand to known suspects from previous cases or that had been printed already.

ACOS 2.2, 2.3 Latent Prints 1.Visible Prints - made by touching fingers to a surface after the ridges have been in contact with colored material such as blood, ink, or paint 2.Plastic Prints - left on soft material such as putty, wax, soap or dust 3.Latent Prints - transfer of body oils; can not be seen by the naked eye

ACOS 2.2, 2.3 Dusting for Prints Powders are brushed onto a non- absorbent surface and will adhere to the oils left by the hand Gray or Black powders are used to life most all prints Specialized clear tape known as lifting tape is used to store the print safely

ACOS 2.2, 2.3 Fuming for Prints Exposing a piece of evidence to fumes of super glue will expose prints – Either combine cotton cloth, sodium hydroxide and super glue – OR – Heat the super glue to allow evaporation

ACOS 2.2, 2.3 Preserve the Print 1.Photograph the print 2.Cover with cellophane tape 3.Place on latent print recovery card 1.Card should be a contrasting color to the color of the powder used

ACOS 2.2, 2.3 Digital Imaging Computers can enhance and darken the print to make an easier image to read.

ACOS 2.2, 2.3