CSI exam 3

arch pattern

ridges enter one side of finger, make a rise, and flow out other side

5% of population

2 types: plain, tented

whorl pattern (circular)

ridges of a pattern flow in a circular

30% of population

4 types: accidental, plain, central pocket, double loop, plain

loop pattern

ridges enter one side of finger, flowing in toward center before recurving and flowing out finger on same side

65% of population

2 types: radial, ulnar

radial loop

flow of patterns runs in direction of radius bone on forearm (toward thumb)

ulnar loop

flow pattern runs in direction of ulna bone ( toward little finger)

how else can loop patterns be described?

right slant- loop flows in direction to right side of persons body

left slant- oop flows in direction to left side of persons body

exemplars (known prints)

collected both from individuals who have legitimate access to scene and individuals who are detained as persons of interest

typically recorded on ten print card

rolled on top, simultaneous (plain/flat) on bottom

simultaneous fingerprints

used to verify the finger sequence and accuracy rolled impressions

what do fingerprint analysts use for analysis?

ACE-V

ACE-V

analysis, comparison, evaluation, verification

analysis

involves assessment of an impression to determine suitability for comparison

comparison

observation of two or more impressions to determine existence of discrepancies, similarities, dissimilarities

evaluation

analysts assess value of details observed during the analysis and comparison steps and reaches conclusion

verification

independent application of the ACE process by another analyst to either support/refute conclusions of original analyst. may be conducted as blind verification

blind verification

independent examination of 1 or more fiction ridge impressions at any stage of the ACE process by another analyst who isn to provided with contextual info and has no expectation of determinations/ conclusion to original analyst

blocking out

conducted once ten print card is recorded

analyst examine each pattern in numbered blocks to determine type and number of ridge counts for existing loop and whorl patterns

must be taken bonfire writing fingerprint classification code

blocking out for arches

plain on index-A, plain on other fingers- a

tented on index- T, tented on other fingers- t

ridge counting not done for arches, classified as either plain/tented

blocking out whorls

plain- W on index, w on remaining

central pocket- C on index, c on remaining

double loop- D on index, d on remaining

accidental- X on index, x on remaining

ridge count designation for whorls

designated as either inner (I), outer (O), or meeting (M) depending on ridge counts

inner (I)

trace passes above right delta

3 or more ridges counted between traced ridge and delta

outer (O)

trace passes below right delta

3 or more ridges between traced ridges and delta

meeting (M)

position of trace is irrelevant

less than 3 ridges counted between traced ridge and delta

blocking out loops

radial loops- R on index, r on remaining

ulna- U on index, forward slash (/) or backward slash(\) on remaining

henry classification system

formula used for efficient filling, manual searching, and retrieval of ten print records

how many divisions in the classification formula?

6: primary, secondary, sub-secondary, major, final, key

what is the difference between the henry and american classification system?

the primary division

primary division

identifies whorl patterns on thumb and fingers of both hands3

Henry primary

american primary

secondary

identifies pattern type appearing on index fingers only (2 and 7)

the small letter group

variation of secondary division which specifies patterns on thumbs and remaining fingers

sub secondary

ridge count designation for loops and whorls appearing on index(2 and 7), middle (3 and 8), and ring fingers(4 and 9)

major division

expressed as fraction, ridge counts for loops or whole on both thumbs

final

ridge count on right little finger if it is a loop. If a loop does not appear on finger #5, then ridge count on left little finger is used if it is a loop

the keys

if two amputed or missing at birth fingers opposite from each other

both given classification of whorls with meet traces (M)

if all ten fingers are missing at birth or amputated

if file becomes too large these modifications were made for easier searching

1. second sub-secondary

2. whorl extensions

3. special loop extensions

if one or more extensions identified in set of rolled fingerprints:

tjheyre expressed in the classification formula directly above the sub secondary

sub secondary

used in sections of filing system where sub-secondary is combo of all inners and outers

whorl extensions

subclassifiying ten print cards when there is large collection of whorls > or equal to 6

special loop extension

appropriate if loop patterns are present on fingers 2,3,4,7,8,9. if loop is present on finger 10, should also be included

national crime information center (NCIC)

computerized info center established for local, state, and federal law enforcement agencies

NCIC fingerprint classification code (FPC)

20 digit alphanumerical code which memorializes pattern type and ridge count corresponding to each finger

NCIC arch pattern two digit codes

plain arches- AA

tented arches- TT

NCIC loop pattern two digit codes

radial- ridge count +50=FPC two digit code

ulnar- ridge count=FPC two digit code

whorl pattern FPC

two digit NCIC FPC code for missing/amputated fingers

XX

two digit NCIC FPC code for scarred/mutilated pattern

SR