2 What is physical Evidence? Any and all objects that can establish that a crime has been committedORCan provide a link between a crime , its victim or a crime and the perpetrator
3 What’s the first thing to do at a crime scene? 1. Secure and isolate crime scene2. Record the scene3. Conduct Systematic Search for Evidence4. Collect and Package Physical Evidence5. Maintain Chain of Custody
4 Secure and Isolate Crime Scene Responsibility of first officer on scene (take steps to preserve and protect scene)First priority - medical assistanceExclude all unauthorized personnelEstablish and Control entry / exit pointsRopes, Tape, Barricades and Guards strategically placed.
5 Once the scene is secure and lead investigator arrives – what happens? Boundaries of Scene determinedDoes the area being searched need to be expanded?Establish perpetrator’s path of entry and exitObvious items photographed and documentedInitial walk through to gain overview and develop strategy for systematic search
6 Name Three ways you could permanently record the scene: 1. Photograph2. Sketch3. Notes
7 Photography Crime scene should be photographed in its entirety. Where the crime happened and adjacent areas.Pictures of evidence to show location and position relative to entire scene.Close-ups to show injuries and physical evidenceMeasuring scale should always be included
8 Videotaping is also useful Long shots and close-upsNarration of events and scenes being videotaped can be useful for later analysis.Sights and sounds of crime scene can be recorded.Provides comparison to determine if scene has been altered or evidence moved during investigation.Still photography continues to be the preference for the majority of crime labs.
9 Sketches Once photographs have been taken, sketches are created. Investigator may not have time or skill so a ROUGH sketch is always created at scene.Finished sketch is finished after all data has been collected.
10 NotesConstant Activity throughout the process of investigating a scene.Notes must include:- detailed written description of the scene- Location of physical Evidence- Records time that each piece of evidence was discovered.- Record who discovered the evidence and how they packaged itNotes should be taken with great detail and in anticipation that this may be the only source of information for refreshing one’s memory after weeks, months or years of an investigation.
11 Search Search for physical evidence must be systematic and thorough. Type of search depends on size and location
12 Collect and Package Physical Evidence Physical evidence must be handled and processed in a way that prevents any change from the time it is removed to the time it arrives at the lab.What are some sources of contamination?BreakageEvaporationAccidental Scratching or bendingLoss through improper Careless packaging
13 Chain of custody Continuity of possession Established when evidence is presented in courtInfo. Collected: initials, date,location of evidenceTo avoid confusion and retain control at all times – individuals on chain of custody should be kept to a minimum.
14 Removal of All evidence must be in accordance with appropriate search and seizure protocols.
15 2 Classifications of Evidence – used for comparison analysis Individual CharacteristicsClass Characteristics
16 Individual Characteristics Evidence that can be associated with a common source with an extremely high degree of probability.Examples:Fingerprints, striation marks on bullets, tool marks, footwear impressions, the comparison of handwriting characteristics, the fitting together of the irregular edges of broken objects (puzzle)
17 Class Characteristics Evidence that can only be associated with a group and never a single source.Most items of physical evidence retrieved at a crime scene cannot be linked definitively to a single person.Examples: Blood type, Layer of paint from a car, carpet fibers, etc…
18 Legal Considerations at a crime scene: Which Ammendment protects us from Unreasonable searches?The 14th AmmendmentA number of allowances have been made by the courts to justify a warrantless search….what do you think they are?Emergency SituationsNeed to prevent immediate loss or destruction of evidenceSearch made by consent of the parties involved.
19 Mincey V. ArizonaCourt dealt with a four day search at a homicide scene.Involved raid on Rufus Mincey – suspected drug dealer.Apt. raided under pretense that Mincey had purchased drugs – undercover agent killed.Guns, ammo, drugs and drug paraphernalia were seized and admitted as evidence in court.Mincey was freed - the 4 day search was illegal.
20 Michigan V. TylerBusiness establishment leased by Tyler and buisness partner destroyed by fire.Fire was extinguished, but it was too smoky to thoroughly search the property…arson was suspected so several items were seized.Investigators returned again the next morning, 4 days later, 7 days later and 25 days later.What evidence do you think was admissible in court?
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