Follow Evidence Part I

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Follow Proof (Part I). Synopsis. Tiny Examination Sorts of Follow Confirmation. Glass Hair (hide) Strands. Paint Soil Shot Deposit. What is Follow Proof?. Approximately characterized, follow proof is little confirmation used to connection casualties, suspects, articles, and wrongdoing scenes. .

Presentation Transcript

Slide 1

Follow Evidence (Part I)

Slide 2

Summary Microscopic Analysis Types of Trace Evidence Glass Hair (hide) Fibers Paint Soil Gunshot Residue

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What is Trace Evidence? Inexactly characterized, follow confirmation is little proof used to connection casualties, suspects, articles, and wrongdoing scenes. Follow examination utilizes magnifying lens and other instrumentation . Different areas (Drugs, Firearms) likewise utilize magnifying instruments.

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Microscopic Analysis Who breaks down follow confirm? Labs areas are organized contrastingly in various labs. Distinctive confirmation could be allocated to various segments (hair:biology, fiber:chemistry) Some labs have follow or microscopy segments.

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Trace > Microscopes Using the Microscope amplifies test. Additionally can take a gander at more point by point attributes of tests. A wide range of sorts of magnifying lens are utilized.

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Trace > Microscopes Microscope phrasing 3-D protest versus Magnifying instrument slide 3-D protest: put any question under the mic Slide: requires readiness Surface examination versus Look through question Surface: Looking at surface of protest (ordinary) Or can sparkle light through straightforward example

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Trace > Microscopes Microscope wording Reflected light versus Transmitted light Refected: bobs off question (ordinary light) Transmitted: goes through protest

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Trace > Microscopes Stereo Binocular Microscope Look at 3-D protests Usually take a gander at surface Usually utilize reflected light

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Trace > Microscopes Stereo Binocular Microscope Preliminary pursuit of articles (garments) for little filaments, hairs, and so on. Take a gander at paint chip layers, measure filaments, projectile striations, and so forth

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Trace > Microscopes Compound Microscope Can be binocular or one visual Look at straightforward question on arranged slide Look through protest Use tr ansmitted light

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Trace > Microscopes Compound Microscope Analyze strands, hair, glass for optical qualities. Organic specimens for sperm cells

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Trace > Microscopes Key terms: Ocular lens Lens in the eyepiece Objective lens Lens over the example

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Trace > Microscopes Key terms: Ocular lens Lens in the eyepiece Objective lens Lens over the example

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Trace > Microscopes Key terms: Micrometer - "ruler" in the eyepiece, considers estimation of test. Amplification - Amount the question is developed Working Distance - Distance between the protest and target focal point

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Trace > Microscopes Polarized Light Microscope (PLM)

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Trace > Microscopes Polarized Light Microscope (PLM) Takes favorable position of the optical properties of glass, precious stones (chemicals), and strands. Test assimilates light contrastingly relying upon its introduction in spellbound light.

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Trace > Microscopes Comparison Microscope

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Trace > Microscopes Comparison Microscope An optical scaffold permits review of proof next to each other. Valuable for contrasting slugs, filaments, hair…

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Summary of Trace Why is follow prove helpful? Gathering follow prove Types follow confirm: Glass Hair (hide) Fibers Paint Soil Gunshot Residue

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Trace Why is Trace Evidence Useful? Can connect questions and individuals. Protest Location Victim Suspect

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Trace Object Trace prove on mallet may include: Blood/Tissue from Victim Blood/Fingerprints from Suspect Fibers from Rug in van

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Trace Location Trace confirm on carpet may include: Blood/Tissue from Victim Blood from Suspect

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Trace Victim Trace confirm on Victim may include: Blood/Semen from Suspect Fibers from Rug in van

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Trace Suspect Trace confirm on suspect may include: Blood/Tissue from Victim Fibers from Rug in van

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Trace How is Trace Evidence Transferred? Locard Exchange Principle : Whenever there is contact between two articles, they will leave or get flotsam and jetsam from the other protest. Amid a wrongdoing, there is dependably be an exchange of confirmation. The trouble is discovering & gathering this confirmation.

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Collecting Trace Evidence Who gathers the confirmation? Cop Crime Scene Investigator Forensic Scientist Depends on the state/group Often one individual to guarantee consistency of marking

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Trace > Collecting Collect follow or whole question? Assume a glove seems to have glass, filaments and blood on it. Ought to the glass, filaments and blood be expelled and bundled independently? Ought to the whole glove be bundled?

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Trace > Collection Considerations before bundling whole protest: Object might be too huge or hard to move Trace proof may tumble off thing amid transport. Follow Evidence might be exchanged to various, immaterial territory of protest. In the case of bundling item, bundle protests independently. Anticipates follow being exchanged to different items.

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Trace > Collection NEVER bundle known material with confirmation. Case in book: Suspect's garments had tar on the knees of jeans. His garments were gathered at the station. Tar was gathered at the wrongdoing scene. The garments and the tar were bundled in a similar sack. Whoops!

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Trace > Collection These 3 strategies should be possible at the wrongdoing scene or in the wrongdoing lab. 1. Visual Inspection 2. Tape Lift 3. Vacuum

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Trace > Collection Visible Inspection Use bare eye or hand focal point. Prove expelled and bundled for later investigation Use brilliant light and forceps to gather.

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Trace > Collection Visible Inspection (Packaging) Small paper envelopes are awful (Holes permit little protests escape). Utilize little plastic sacks, glass vial or paper utilizing a pharmacist crease. Twofold bundle. Mark each bundle.

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Trace > Collection Tape Lift Clear tape is utilized. Over and over apply tape to little zone until the greater part of the stickiness is no more. Tape is collapsed back upon itself, taped to a glass slide or taped to a bit of plastic. Put in discrete named compartment. Make sure to record particular range secured.

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Trace > Collection Vacuuming Nozzle ought to be short and straightforward. Flotsam and jetsam is gathered on a channel or layer

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Trace > Collection Vacuuming Small region is vacuumed. (Channels changed much of the time) Filters bundled in partitioned marked compartment. (Make sure to record particular territory secured) Most disgracefully utilized technique since it regularly brings about the gathering of a ton of unimportant material.

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Trace > Analysis To distinguish the wellspring of the gathered confirmation. What is the reason for investigation? Fiber recuperated from casualty. Source: Matches strands from floor covering in presume's van Soil found on Suspect's shoe Source: Matches soil at wrongdoing scene Blood found on speculate's sofa Source: Matches blood of casualty

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Trace > Analysis The Catch: With follow prove, an examiner more often than not can't state that one bit of confirmation certainly started from a particular thing. The agent can just tell the jury what similitudes were found and give them a thought of how uncommon those likenesses are.

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Trace > Analysis Classifying Evidence: Most follow proof is characterized utilizing class attributes (shading, shape, refractive file, and so forth.) When looking at class qualities, supreme distinguishing proof is unrealistic . The Forensic Scientist's fundamental target is to give the jury a thought regarding how uncommon the class is .

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Trace > Analysis Classifying Evidence: If physical properties vary , they didn't originate from a similar source. Prohibition is conceivable .

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