第三场讲座“世界名案分析”大纲ShootingInvestigation

1、Shooting Case InvestigationDr. Henry C. LeeChief Emeritus, State Police LabProfessor, University of New HavenDirector, Forensic Research & Training Center1Type of firearmsHandgunsRiflesShotgunsSubmachine gunsMachine guns2COMPONENTS OF A FIREARMBARRELRifled or SmoothSTOCK OR GRIPFIRING MECHANISMFirin

2、g Pin, Breech Lock, Ejector, ExtractorLOADING MECHANISMSingle, Automatic, double barrelMAGAZINE OR CYLINDER3AMMUNITION COMPONENTSProjectileBullet, shot pellets, slugCartridge Case / ShellPrimerCenter v. Rim firePowderBlack PowderSmokeless (Nitrocellulose base)Wad4BULLETS - PROJECTILESCALIBER, GUAGE,

3、 SHOT SIZECOMPOSITIONCLASS CHARACTERISTICSMANUFACTURER, STYLETYPE WEAPON FIRED FROMINDIVIDUAL CHARACTERISTICSSTRIATIONS FROM LANDS & GROOVES5CARTRIDGE CASESMANUFACTURERCALIBER & LOAD SPECIFICATIONSFACTORY V. RELOADINDIVIDUAL CHARACTERISTICSFIRING PIN IMPRESSIONBREECHFACE MARKCHAMBER MARKSEXTRACTOR /

4、 EJECTOR MARKS6WEAPON EXAMINATIONSFUNCTIONALITY PROPERTRIGGER PULLTRACE / FINGERPRINTS / DNAOWNERSHIP HISTORY7TOOL MARK COMPARISONSTYPESIndentations, StriationsDOCUMENTATIONPhotos, Seize item, Casts, REPRODUCTION / EXEMPLARSSuspect tool, similar surface-motion-pressureTRACE ANALYSISPaint analysisCOM

5、PARISON MICROSCOPENUMBER RESTORATIONS8Serial NumberRestorationPolish surfaceApply etching acid9Shooting Incident ReconstructionShooter location / position determinationVictim location / position determinationHomicide / Suicide /Accidental deathTrajectory determinationDistance determinationSpatial an

6、d sequence determination10Communication with HQAid victimsLocate witnessesSecure the sceneTransfer officer involved crowd controlDocumentation of the sceneCollection of physical evidenceInitiate investigation11Information witnessstatementsTheoryRecord FilesceneLaboratory resultsPhysical evidence12Gu

7、nshot wounds13Kinetic Energy Of A Projectile K.E. = M V14Classification of Gunshot WoundsContact woundsNear contact woundsIntermediate Gunshot woundsDistant wounds151617Wound EvidenceEntrance woundAbrasion RingsPowder SootPower particlesExit WoundTrace MaterialPseudo-Powder TattooingBullet Wipe18SHO

8、T GUN INJURY PATTERN19TYPESContact DischargeClose DischargeMid-range DischargeDistance Discharge 20Contact DischargeMuzzle against the skin Single and circular woundEntrance hole approximate diameter of boreLittle or no soot on skinLittle or no burn on skinMuzzle mark on skinGSR in wound track21Clos

9、e Range DischargeMuzzle near skin (not a contact)Circular Wound right angleElliptical wound slanted angleNibbling / cremation around wound edgeBlackened / soot on edge of woundAnnular / distant bruisingSingeing of hair / skinGSR around wound22Mid-range DischargeSmoke / soot diminished 20-40cmMuzzle

10、to target 15cm to 2 mPowder tattooing around wound 20-6- cmCremated / scalloped wound edgesOne central entrance hole 1mSatellite holes around central hole 1m23Distance DischargeMuzzle to target - 2mNo burning / soot on skinFew GSR particlesWad may be present 5mCentral hole diminished 6- 10 mSpread o

11、f pellets increase 24Trace Evidence in Shooting CasesResidues on Bullet and CasingResidues along Projectile pathGSR on HandsGSR on ClothingGSR on TargetBlood Spatters on Body and SceneTrace materials on ClothingBlood, Tissues on Weapon25Trace and Transfer EvidenceHairFibersTissuesSalvia BloodstainsG

12、SR PatternsSoil StainGrass Stain 26GSR (Gun Shot Residue) DepositsGSR from MuzzlePowder Particles on Target (Body, Wound, Clothing, Object, Surfaces)GSR from Cylinder gapGSR particles on Hands, Clothing 27GUN SHOT RESIDUEBURNED & UNBURNED POWDER PARTICLESPRIMER RESIDUE:LUBRICANTSBARREL RESIDUES / TR

13、ANSFERSPROJECTILE WIPES / TRANSFERS28Bullet Trajectory DeterminationProbeStringlaser29Alignment of laser beamDocumentation of laser beamPositioning stagesAngular information from the aligned beamInterposition of objects in the laser beamThe use of hollow probes with laser beamDual- opposed co-axial

14、laser beamHigh ambient light level, auxiliary alignment target30Problems associated with shooting reconstructions Damage to the bulletThrough and through shotsAlteration of pattern evidenceInability to recover evidence alteration of physical evidenceMisinterpreted information 31General Consideration

15、 of RicochetThe projectile will lose some energyThe depart is usually different than the incident angle The projectile usually has deformationTrace transfer evidence usually presenceImpact surface may play important role32Laws of Physics on RicochetThe Steeper the incident angle, the greater the for

16、ce acting on the bullet at impact.The greater the impact on the bullet results the greater loss of velocity and the greater deformation to the bullet.33Important TermsIncident Angle vs. Departure Angle, Critical AnglePinch Point, Bow effect & Chi sum TrailLead Splash vs. Lead wipeHard Surface vs. So

17、ft Surface34Ricochet & DeflectionRicochet is the continued flight of a rebounded projectile after an actual angle impact of a surface or object. Deflection is a deviation in the projectiles normal path as a consequence of an impact.1. As a consequence of a ricochet2. As a consequence of a penetratio

18、n35Examination of Ricochet Bullet Bullet DeformationBullet DestabilizationBullet Deflection36Bullet Ricochet Surface1. Yielding Surface: Soil, Sand, Water, Tissue, Sheet Metal, Wood, Drywell2. Frangible Surface: Cinder Blocks, Bricks, Stepping Stone, Procaine Surface3. Non Yielding Surface: Stone, Concrete, Steel, Heavy Metal37Portland - A Shooting Investigation