foot and tool impression

7/25/2019 Foot and Tool Impression

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TOOL IMPRESSION

or TOOLMARKS


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What are TOOLMARKS?

Are impressions or marks produced by atool or instrument on a receptive surface.When a tool makes contact with the

surface with sucient impact to createindentation, the pattern of the tool ispermanently reproduced onto thesurface.


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Characteristics oftoolmarks

Toolmarks have two characteristics,namely:

CLA C!A"ACT#"$T$C % includes its &eneral shape,the type of impressions, and its &eneral dimensions.Class charac. Allow the e'aminer to identify what typeof tool created the impression and how the mark iscreated.

$()$*$)+AL C!A"AT#"$T$C % or accidentalcharacteristics are the striations e'hibited by the tool,which are uniue to a certain tool. They consist ofsmall, commonly microscopic, rid&es, indentation, and

irre&ularities present on the toll itself.


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Class characteristics

I!i"i!#al characteristics


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T$%es of toolmarks

There are two main type of toolmarks,namely:

L$--#) $-"#$/( 0 occurs as the toolis dra&&ed across the surface, resultin& intool marks comprisin& a series ofstriations runnin& parallel to each other.

/L)#) $-"#$/( 0 results from thecontact of a tool onto a surface with a nolateral motion1no dra& nor slip2.


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Sli%%e! im%ressios

Mol!e! im%ressios


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E"i!ece s#&mitte! i toolmarkcases ma$ icl#!e tools' s#ch as(

% bolt cutters % scissors %saw, knives % screwdrivers, chisels Crowbars tire irons % pliers, wrenches


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Places a! s#rfaces )here toolmarksmi*ht &e o&ser"e i crimial

i"estifatios(

% human bone and cartila&e % doors and window frames % section of sheet metal % padlocks, doorknobs % wire, chains % bolts and locks

afety deposit bo'es and safes


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FOOT IMPRESSION

or S+OE PRINT


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KINDS OF S+OE PRINT(

-AT#(T !/#-"$(T 0 are clearly visible and comefrom trackin& throu&h a substance such as pain or dirt,leavin& some of these behind each time a step is taken.4or e'ample, bloody shoe prints left on 5oorin& or tracks

left by muddy tires on a driveway.

-LAT$C !/#-"$(T 0 occurs when a shoe sinks into asoft substance such as mud.

LAT#(T !/#-"$(T 0 are not visible to the naked eyeand often occur on a hard surface such as &lass or

concrete. #'aminers or investi&ators use powders,chemicals or alternate li&ht sources to 6nd these prints.#'amples include shoeprints detected on a tile orhardwood 5oor, window sill, or metal counter, or tire tracksdetected on road surfaces, driveways or sidewalks.


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-LAT$C !/#-"$(T

LAT#(T !/#-"$(T

-AT#(T !/#-"$(T


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What are CASTS a!MOLDS?

CAT 0 a reproduction of an ob7ect thatmade the impression1a positive replica2

/L) 0 a reproduction of the impression

made by the ob7ect1 a ne&ative replica2 -/$T$*# "#-L$CA 0 the obtained cast

from an impression made in soil, dust,blood, etc.

(#8AT$*# "#-L$CA % the impressionitself, indented into the soil, dust,blood ,etc.


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MO,LA-E a!POSMO,LA-E

/+LA8# % is a water based &el which can bereused several times. $t 5ows freely at warmtemperature 199 0 9; de&rees 4.2 but be&ins toharden at about 9 de&rees 4. and because of its

warm temperature, .moula&e may be used tomake a molds of body of a livin& individual.

-//+LA8# 0 is a wa' based material which isused to make a positive replica of the ori&inal

ob7ect from a moula&e mold. -osmoula&e may beheated directly. $t will 5ow freely at 9


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WA.S IN COLLECTIN-FOOTPRINTS(

AD+ESI/E LIFTER% a heavy coatin& of adhesive lifts theimprint from smooth, non%delicate surfaces such as tile orhardwood 5oors, metal counters, etc. $t is usually used incon7unction with 6n&erprint powders.

-ELATIN LIFTER% a sheet of rubber with a low%adhesive

&elatin layer on one side that can lift prints from almost anysurface, includin& porous, rou&h, curved and te'turedsurfaces. $t is less tacky and more 5e'ible than an adhesivelifter, allowin& it to pick up a dusty shoeprint on a cardboardbo', for e'ample, but not tear the surface of the bo'.

ELECTROSTATIC D,ST0PRINT LIFTIN- DE/ICE% a toolthat electrostatically char&es particles within dust or li&htsoil, which are then attracted and bonded to a liftin& 6lm.This method is best for collectin& dry or dusty residueimpressions on almost any surface


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ELECTROSTATIC D,ST0PRINTLIFTIN-

foot and tool impression

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