Xã hội học - Injury and death investigation

When a bullet penetrates the skin: the skin is pressed inward the skin is stretched and perforated the skin then returns to its original position

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NINEInjury and Death InvestigationLEARNING OBJECTIVESDescribe the four motivational models for classification of homicide Identify the investigator's responsibilities when responding to the scene o suspected homicide or assault Comprehend the importance of personal identification of a victim in a homicide investigation Outline the major elements in a search for buried bodies Understand the individual observations used collectively to determine the time of death Discuss the five most common types of wounds encountered in injury and death investigationsAssess information used by investigators to distinguish between a homicide and suicide Outline facts that need to be determined in the investigation of fire deaths Define stalking and identify common categories of stalking Describe what items are needed for a psychological profile9-1HOMICIDESExcusable Homicide: The difference between justifiable homicide in that one who commits an excusable homicide is at some degree at fault but the degree of fault is not enough to constitute a criminal homicide.Felonious Homicide: Treated and punished as crimes and typically fall into two categories: murder and manslaughter.Justifiable Homicide: The necessary killing of another person in the performance of a legal duty or the exercise of a legal right when the slayer was not at fault.9-2MOTIVATIONAL MODELS FOR CLASSIFICATION OF HOMICIDE Criminal Enterprise HomicideCriminal enterprise homicide entails murder committed for material gainPersonal-Cause HomicidePersonal-cause homicide is motivated by a personal cause and ensues from interpersonal aggression9-3(a)MOTIVATIONAL MODELS FOR CLASSIFICATION OF HOMICIDE (cont'd) Sexual HomicideA sexual element (activity) is the basis for the sequence of acts leading to deathGroup-Cause HomicideTwo or more people with a common ideology sanction as act, committed by one or more of the group's members, that results in death9-3(b)RESPONDING TO THE HOMICIDE SCENE When responding the investigators should: proceed with deliberation not reckless speedbe observant for a fleeing suspectbe suspicious of vehicles leaving the scenebe alert to an individual trying to hide9-4INVESTIGATOR’S RESPONSIBILITIES UPON ARRIVAL AT THAT SCENE OF A HOMICIDE Scene safetyDetermining scene safety for all investigative personnel is essential to the investigate processConfirm or pronounce deathAppropriate medically trained personnel must make a determination of death prior to the initiation of the death investigation 9-5(a)INVESTIGATOR’S RESPONSIBILITIES UPON ARRIVAL AT THAT SCENE OF A HOMICIDE (cont'd)Participate in scene briefing with attending agency representativesScene investigators must recognize the varying jurisdictional and statutory responsibilities that apply to individual agency representativesConduct a scene walk-throughConducting a scene “walk-through” provides the investigator with an overview of the entire scene9-5(b)IDENTIFICATION OF THE DEAD PERSON Personal identification of the dead person is important because: Delay in doing so complicates the investigationDelay makes it difficult to focus the investigationDelay makes it difficult to understand who would benefit by the death9-6THE SEARCH FOR BURIED BODIES PreplanningOne important facet of major case investigations is administrative preplanning, an area that is frequently and unfortunately neglectedDiscoveryMany buried bodies come to light accidentally. Occasionally, information is received that a body is buried at a particular location; these cases will be considered laterExcavationThe surface of the grave should now be carefully cleared of extraneous material9-7(a)THE SEARCH FOR BURIED BODIES (cont'd) The BodyWhen the body is uncovered and has tissue remaining on it, the forensic pathologist may make an on-scene cursory examinationSearch for a Buried BodyIn some cases, information is received through an informant, a citizen, or a confession that a body has been buried, and an approximate location is givenUse of Cadaver DogsDogs have been used in a variety of forensic contexts because of their superior sense of smell9-7(b)SKETCH IDENTIFICATIONTo reconstruct and identify bodies police may be assisted by:physical anthropologistspolice artistslocal/national media9-8(Source: Federal Bureau of Investigation)EXCAVATION SITEBefore excavating the body investigators should:photograph the burial sitehave maps made to show both plane and elevation viewsand to tie in items found by both horizontal location and depth9-9(Source: Courtesy Federal Bureau of Investigation)CADAVER DOGCadaver dogs when properly trained can:detect buried bodiesfind submerged bodies9-10(Courtesy Bob Westenhouser Tampa Tribune)INDIVIDUAL OBSERVATIONS USED TO ESTIMATE TIME OF DEATH When used together the following individual observations of a body may be used to estimate the time of deathbody temperaturerigor mortislivor mortisdecomposition changesstomach contents9-11EVIDENCE FROM WOUNDSFirearm WoundsWhen a bullet strikes a body, the skin is first pushed in and then perforated while in the stretched stateFirearm residues Detecting firearm residues on the hands of an individual may be of great importance in evaluating deaths due to gunshot wounds9-12(a)EVIDENCE FROM WOUNDS (cont'd)Incised and Stab WoundsPuncture WoundsLacerations In an assault these wounds are caused by clubs, pipes, pistols, or other such blunt objects9-12(b)EVIDENCE FROM WOUNDS (cont'd)Defense WoundsDefense wound are suffered by victims attempting to protect themselves from an assault, often by a knife or clubStrangulation WoundsLigature strangulation. The pressure on the neck is applied by a constricting band that is tightened by a force other than the bodyManual strangulation. Pressure of the hand, forearm, or other limb against the neck, compressing the internal structures of the neck9-12(c)A BULLET PENETRATING THE SKINWhen a bullet penetrates the skin:the skin is pressed inwardthe skin is stretched and perforatedthe skin then returns to its original position9-13(Source: Barry A. J. Fisher, Techniques of Crime Scene Investigation, © 1992, reproduced with permission of copyright owner, CRC Press, Boca Raton, Florida)CONTACT BULLET WOUNDContact shots against an exposed part of the body drive soot, metallic particles and powder into the bodyThese materials may be recovered during the autopsy9-14(Courtesy Santa Ana, California, Police Department)INCISED WOUNDSTypically bleed a lotAre inflicted with knives or razorsAre narrow at the edges and gaping in the middle9-15(Courtesy Federal Bureau of Investigation)COMMON TYPES OF WOUNDSType of WoundCharacteristicsFirearm: Contact (muzzle against body) Close (less than 18 inches) Distant (18 inches or more) No blackening around entry; star-shaped, often with flaps directed outwardBlackening around entry; grains of powder and deposits of powder residueNone of the above characteristics appearIncisedCutting wound inflicted with sharp-edged instrument, wound typically narrow at ends and gaping in middle with a great deal of bloodStabAs above; manner in which knife is thrust into and pulled out of body can result in wounds of different shapes made with same knifePunctureCan be caused by ice picks, leather punches, and screwdrivers; result in small wounds with little or no bloodLacerationsOpen, irregularly shaped wounds, caused by clubs, pipes, pistols and other blunt instrument wounds accompanied by bruising or bleedingDefensesCommonly found on palms of hands, fingers, forearmsStrangulation: Ligature ManualMark encircling neck in a horizontal plane overlying larynx or upper trachea; sometimes broken at back of neck where hand grasped ligature; abrasions and contusions of skin not usually presentAbrasions, contusions and fingernail marks on skinREASONS FOR SUICIDEIll healthSevere marital strifeRecent emotionally damaging experienceFinancial difficulties9-17(a)REASONS FOR SUICIDE (cont'd)Perceived humiliationActual humiliationRemorse over loss of loved oneRevenge9-17(b)TYPES OF SUICIDE9-18MethodEvidence and ProcedureShootingMost commonly a gunshot to the temple; frequently no exit wound; investigators look for blood spatter, gunshot residue, and hammer-spur impressions on decedent’s hands.HangingNeck is rarely broken; feet or knees are often touching the ground—only when unconsciousness occurs is full weight of body applied to noose, resulting in cutoff of all oxygen to the brain and thus death; petechial hemorrhaging in eyes commonIngesting pharmaceuticalsInterviews with relatives, friends, neighbors can help determine whether death is accidental or suicidal; especially difficult because of possible unexpected interactions among drugsDrowningChest cavity and lungs distended and soggy; heart flabby, with right side dilated and filled with dark red fluid; hemorrhaged mastoid cells in ear; water in stomach and duodenum; algae in body; parts of lips, ears, and nose often eaten awayCuttingInvestigators look for hesitation marks—series of lesser wounds in general region of fatal wound; self-inflicted throat wounds deep at point of entry, shallow at terminus; not unusual to see a series of cuts on different parts of the bodyIngesting poisonMat be signs of vomiting & severe damage to lips, tongue, and mouth; victims may employ second means of suicide because death does not occur rapidly; search for poison container critical; details under “Pharmaceutical,” above, also applyInhaling gasCarbon monoxide, most common, causes skin to turn bright redJumpingWitness interviews and assessment of victim’s predisposition to suicide criticalIntentionally crashing automobileUsually a single occupant speeding into an off-road obstacle; lack of skid marks; shoe-sole imprints from gas and brake pedals sometimes usefulCOMMON REASONS THAT HIT-AND-RUN DRIVERS FAIL TO STOPThe driver had been drinkingThe vehicle was stolenThe driver had a suspended or revoked operator's license There was someone in the car whose presence, if discovered, could cause additional problems, e.g., someone else's spouse9-19(a)COMMON REASONS THAT HIT-AND-RUN DRIVERS FAIL TO STOP (cont'd)The driver had no liability insuranceThe driver or a passenger was injured requiring the driver to drive directly to the nearest emergency roomThe driver did not realize he/she had been involved in an accidentThe driver had committed a crime just prior to the accident and still had evidence of it in the vehicle9-19(b)FACTS TO BE DETERMINED IN FIRE DEATH INVESTIGATIONS Coordination and CooperationCoordination of and cooperation between police and fire investigators are of paramount importance in the successful investigation of any questioned fireDegrees of BurningBurns are medically classified into four typesIdentification of RemainsBecause fire destroys human tissue, identification of the remains may be especially difficultScene ConsiderationsAs with any physical evidence, burned bodies must be sketched, measured, and photographed9-20(a)FACTS TO BE DETERMINED IN FIRE DEATH INVESTIGATIONS (cont'd) Examination of the External BodyThe body of the deceased should be examined in detail both at the scene and again at the morgueExamination of the Internal BodySoot, other debris, or burning in the air passagesToxicology ExaminationThe pathologist should take samples for later examination by a toxicologistHistologic ExaminationMicroscopic examination of tissues is also an important part of the postmortem examination9-20(b)FACTS TO BE DETERMINED IN FIRE DEATH INVESTIGATIONS (cont'd) “Flash” FiresConcentrated burns in one area of a body may indicate the nature and cause of deathMotives of Fire DeathsIn fire deaths, various motives should be kept in mind by investigatorsRecording the ScenePhotographs of the body in its original position and of the room or area in which it is found9-20(c)STALKING Stalking is harassing or threatening behavior that an individual engages in repeatedly, such as following a person, appearing at a person's home or place of business, making harassing phone calls, leaving written messages or objects, or vandalizing a person's property. Legal definitions of stalking vary widely from state to state.9-21STALKERS Demographically. Stalking is a gender neutral crime, with both male and female perpetrators and victims. However, most stalkers are men.Common categories of stalkersLove Obsession StalkersSimple Obsession StalkersCyberstalking9-22NATIONAL CENTER FOR THE ANALYSIS OF VIOLENT CRIME (NCAVC) Designed to form a partnership among federal, state, and local law enforcement agencies in the investigation of potentially related, unsolved violent crimes9-23CRIMINAL INVESTIGATIVE ANALYSIS Criminal investigative analysis, formerly referred to as psychological profiling, is the analysis of crime scene patterns in order to identify the personality and behavioral characteristics of offenders who commit serial crimes of rape and homicideThe concept of criminal investigative analysis works in tandem with the search for physical evidence9-24(a)CRIMINAL INVESTIGATIVE ANALYSIS (cont'd) Psychological evidence, like physical evidence, varies, and so the profile may also varyProfilers need wide exposure to crime scenes to discern patterns and some exposure to criminals who have committed similar crimes9-24(b)

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