The Crime Scene
PROCESSING THE CRIME SCENE
A.- aulomobilcs run on gasolir.e, crime laboralories "run" on physical cvidcnce. Physical cvideiice cncompasscs any and all objects tbat can establish that a crime has bcen committed or can provide a link between a crime and its victim or a crime and its perpetra-tor. BuL if pjv/sical evidcnce is tn be cíTectively uscd foraiding Ihe inves-tigator, its prescnce first musí be recognized at the crime scene. If ali the natural and commcicial objects within a reasonable distance of a crime were gathercd so that thc scientist could uncover significant clues from them, the dcluge of material would quickly immobilize the labora-tory fácil i ty. Physical cvidence can only achicvc its optimum valué in criminal investigationswhcn its collection is performed with a selectiv-ity govcrncd by thc collector's thorough knowledgc of the crime labora-torv's tcchniques, capnhilities. and li mitations.
Forthcoming cha|)tcrs will he devoted to discussions of methods and tcchniques available to Corcnsic scientists for thc cvaluation of physical cvidence. Although it is truc that present-day technology has givcn the crimelahoratory capabilities far excccding those of past decades, thcse advances are no excuse for complacency on thc part of
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criminal invesligalors. Crime laboratorios do noL solve crimes; only a thorough and compeLenL investigalion conducLed by proíessiohal pólice oíficers will enhance Lhe chances íbr Lhe succcssí'ul ouLcome oí a crimi¬nal invesLigaLion. To be snre, íbrensicsciencc is, and will continué Lo be, an important elemenL oí Lhe loial invesligalive process; buL iL is only one aspcct oí'an endeavor LhaL musí he a Leam eí'íbrl. The investigator who believcs Lhe crime laborat.ory Lo be a panacea for laxiLy or inepLncss is in for a rude awakening.
Forensic science begins aL the crime sceno. I ('Lhe investigator ean-noL recognize physical evidence or cannoLpropcrly preserve il íbr labo-raLory examinaLion, no amounL oí'sophisLicated laboralory inslrumen-LaLion or Lcchnical experti.se can salvage Lhe siLuaLion. TJxc J.!'>-aulhorized access Lo Lhe ai'ea.
Sometí mes the exclusión oí' unaulhori/.od personnel proves Lo be a more diílicull task Lhan expecLed. Crimes oí violence are especiaIIy sus ceplible lo allcnlion by hight-r level pólice ol'íicials andmemliL-i-s oí'the press, as \vcll as by c-oiol u mal I y rhargvd nci^hbors and i-u riosi t ' sc'ck-ers. Every individual who enlors Lhe scene is a polenlial deslros'er o!
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pbysica! cvidcnee, e-ven il'iL is by u ninlenlional earelcssness. lí'proper control is lo be cxerciscd over I be crime sccnc, Ibe oCficer charged willi Lhe responsibihly Cor prolccling it musíbave Lbc aulhorily Lo cxclude everyonc. includmg" Icllow pólice oííicers noL dircel.Iy mvolvecl m pro-cessing Lbe site or ni conduclmg Ibe invesligalion. Scasoncd criminal i nvestigalors are always preparcd Lo reíale horror slorics aboul crimc scencs made LoLally valuelcss for physicnl cvidence by bordes oí'pcople wbo, Cor one reason or anoLber, Irampled Lhrough Lbem. Sccurmg and isolaling Lbeeriine seene are criLical stops in an invcstigalion, Lbe accompl ¡shmenL oí" \vbich is Lbe mark of a Lrained and profcssional crime-scene i nvesLigalive Leam.
¡tECOKD Tul-: SCIMK
I nvesligalors will bavc onlv a limiLed amounL oClimc Lo work a crime siLe in iLs unlnuchcd sLaLe. 'Une opporlumly Lo pcrmancntly record Lbc scene in iLs original sLaLe musí nol be losL. Sncb records will noL onlyprove use1 fu I clunng Lbc subse(]LienL i n vcsLigalion, bul Lhcy are also r(.H|Liircd Cor prescnlalion aL a Lnal in ordei" Lo document Lhe condiLion oC Lbe crime siLe and Lo delinéale Lbe localion oC pbysical cvidence. I^b_o.-logi^aphy, skelchcs, and notes are Lbc tbrcc mclbods for crime-scene recording (Kigurc 2-1 ). Ideally al! l.hree should be cmploycd; however, as is o Cien (be...