WHY FINGERPRINTS? Fingerprint evidence is the most positive investigative means for identifying people. Fingerprints form on a person before birth and remain unchanged until the body decomposes after death. Every fingerprint is unique!
WHAT IS A FINGERPRINT? A fingerprint is a pattern of friction ridge details, that are comprised of ridges and valleys. A Ridge – is a high. A Valley – is a depression or low. Friction ridges are also found on our palms, feet and toes.
THE PATTERN The pattern is the unique characteristics of the ridges and valleys that make up the print. It is defined by the spatial relationship of lines with each other, their beginning and terminating points, and the unique pattern they make. The genes from our parents determine the general characteristics of the patterns.
FINGERPRINT IDENTIFICATION 1. What are fingerprints? Recorded impressions of the friction ridges located on the surface of the finger. 2. What is the purpose of fingerprint identification? To establish the identity or non-identity of two sets of fingerprints.
FINGERPRINT IDENTIFICATION 3. What are fingerprint characteristics? These are also known as ridge detail, points of identification, or identifying characteristics. Ending Ridges Bifurcations Dots Enclosures Short Ridges
FINGERPRINT IDENTIFICATION 4. How are fingerprints compared? Fingerprints are compared by noting the ridge characteristics on two prints to determine whether or not they match. An identification is established when a number of these characteristics occupy the same relative position on the two prints.
FINGERPRINT IDENTIFICATION How many points of identification (characteristics) are sufficient to establish an identification? A. No set standard number required. B. Left to each individual fingerprint examiner. C. Deciding factors: 1. Clarity of impressions 2. Uniqueness of formations Fingerprint examiners experience and ability
POINTS OF IDENTIFICATION United States No Set Numbe England 16 France 17 Germany 12
FINGERPRINT IDENTIFICATION Be extremely cautious! The integrity of the identification process depends on the fingerprint examiner devoting his or her attention to comparison work at all times. Always be certain that the fingerprints have been printed in the proper finger blocks. Be absolutely certain of your decision NOTE: As many as 150 ridge characteristic can be noted in the average fingerprint.
Ending Ridge Enclosure Trifurcation “T” Junction Ridge Crossing Bifurcation Short Ridge Row of Dots Dot RIDGE CHARACTERISTICS COMMON OCCASIONAL RARE
1 11 10 2 9 3 8 4 5 7 6 RIDGE CHARACTERISTICS MAGNIFIED Points 1, 2, 4, 5 are Ending Ridges Points 3 and 9 are Dots Points 8, 10, 11 are Bifurcations Point 6 is an Enclosure (ISLAND) Point 7 Short Ridge
Second observation should be to examine the line of flow.
Third observation should be fingerprint characteristics. Looking for the most obvious point(s) of identification (i.e., what captures your eye first).
HOW TO COMPARE FINGERPRINTS
Fourthobservation is to ensure the characteristics are in the same relative position.
Count from one characteristic to another. Look for characteristics that are alike. Remember that inking, pressure,occupation,failure to roll fingerprints nail to nail and scars can change the appearance of characteristics.
“THINGS TO REMEMBER” Look for theobviouscharacteristics Utilize theentirefingerprint Never base your decision on ascar Never non-ident byonefinger only Ensuresequenceis correct Unablewhen not 100% positive of decision Utilize existingenhancementtools Takesufficient time to process Avoiddistractions& beware ofcomplacency Maintaingoodwork habits