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1 Unit 3 Crime Scene Processing & Analysis Processing vs. Analysis Analysis depends on Detailed observations Proper procedures Logical connections Results of lab tests Scene patterns Integrating all data If there was a death forensic pathologist Processing vs. Analysis Follows scientific method Most crime scene investigators are not usually forensic scientists Most are police personnel that learned their specialty through training and experience Most times scene processing is not done by the same individuals who will do the lab analysis Types of Scenes No scene white collar crimes, extortion, DUI, prostitution, internet crimes, drug dealing Property crimes Larceny, burglary, auto theft Crimes against persons Assault, battery, sexual assault, robbery, attempted murder, murder Types of Scenes Indoor vs. Outdoor Indoor protects against elements Outdoor evidence can be destroyed or compromised by weather Private vs. Public Property Public lots of human activity and often difficult to secure First priority protecting a victim, a fellow police office, or themselves EMS try to do as little damage as possible to the crime scene First responders often a uniformed patrol office who is first on the scene Often called to the scene - 911

2 Need to decide whether to continue investigating without a search warrant Call supervisor CSI Unit Medical examiner Prosecutor's office Crime scene security limiting and controlling access to a crime scene and maintaining records of those who were there tape Preserving the integrity of the scene the more public the scene, the more difficult this will be Sometimes the initial barrier must be extended depending on the evidence found PRELIMINARY Proceed promptly and safely Render aid and assistance Effect preliminary notifications Locate witnesses Investigate briefly and secure the scene Maintain control Interview witnesses Note all conditions Arrest suspects ads appropriate Report fully and accurately Yield to continuing investigation Making sure that no one enters that does not a have a necessary role Elimination fingerprints, DNA swabs, and pictures Name and contact information of all witnesses and others that may have information Sometimes a crime may have more than one scene Dumpsite secondary location where a body was left Less evidence than crime scene Steps in Scene Processing and Analysis Scene Survey and Evidence Recognition Scene survey preliminary walk-through Special attention to transient evidence Evidence that can easily be destroyed or compromised Footprints, Tire prints can be stepped on or driven over Pattern of objects moves by first responders, EMS Evidence recognition determination of which physical evidence items and/or patterns are relevant to the case as opposed to being part of the background

3 Steps in Scene Processing and Analysis Scene Searches a detailed, systematic search of a crime scene with the objective of noting every condition and every relevant item of physical evidence All scene searches must be THOROUGH Many times there are no second chances to go back and search again creation of a detailed, complete record of a crime scene, including notes, sketches, photographs, and possibly audio or video tape Allows someone to reconstruct every detail of the scene Many patterns/items of evidence can not be collected (stationary items) Steps in Scene Processing and Analysis Only after documentation has been completed Evidence deemed as relevant and appropriate for collection, packaging, and preservation can be placed into appropriate, properly labeled containers Steps in Scene Processing and Analysis Release of the Scene- when investigators are satisfied that they have thoroughly documented the scene and all associated evidence and that they have recognized and collected, where appropriate, every relevant item Once a scene has been released, it is usually not possible to collect anything else There is no longer a direct chain of custody Evidence collected after a scene has been released could be ruled inadmissible in court Scene Survey and Evidence Recognition The step that is most dependent on the training and expertise of the CSI team Investigators follow the scientific method Data/Observations/Witness Statements Hypothesis may be revised as the investigation goes on Testing hypothesis Against scene pattern information and investigative information Against lab results and medical examiner results Additional experiments pertaining to the evidence Formation of a theory Reconstruction using the best theory Scene Survey and Evidence Recognition Working Hypothesis An initial theory about what may have happened in a case based on observation of the crime scene Can generate predictions about physical evidence that are testable during the investigative, laboratory, and medicolegal stages of analysis Scene Searches Spiral search starting from the center of a room and working outward Strip/line search most effective in areas where visibility is low forests Grid search large, outdoor areas Zone/quadrant indoor and vehicles

4 Scene Searches EVERY piece of documentation should include the following Date Time Location Case number Person making the record For sketches both the sketcher and measurer must be listed For evidence A description of the item The item number Notes Anything that cannot be photographed, sketched, or video-recorded Important to take notes about everything even those that can be photographed, sketched, or video-recorded Initial conditions Names/contact information of witnesses License plates of vehicles in the vicinity Notes can also be audio-recorded First responders are the ones to observe the crime scene as close as possible to its original condition Fresh in their memories Smells Doors/windows locked/unlocked; open/shut Basis for more formal reports Logs who was there and time signing in and out Continuously running video Photo log what photos were taken Evidence log Scene checklist must be completed before scene is released Sketches Drawing of scene with measurements or to scale showing the exact location all of all permanent fixtures and evidence Can provide information that photographs and videos can not due to distortion and the perspective of the photographer Types of sketches Rough/preliminary Made at the scene during processing Not to scale Contains measurements Smooth/finished Prepared later Drawn to scale (scale is indicated) Irrelevant items are eliminated

5 Cross-projection 3-D sketch in 2 dimensions drawn by collapsing the walls and the ceiling flat in the sketch Bullet holes Blood splatter Dimensions must be measured Several methods are used to determine the exact location of objects Triangulation on 2 fixed points Single fixed point Using a fixed point and a 90 o angle XY axis Walls must be at 90 o angles to each other Can also be done with computer programs Hand notes should be kept to verify sketches GPS can also be utilized Rough/Preliminary Sketch Smooth/Finished Sketch Cross-Projection Sketch Photography 2 aspects Technical understanding of and skills in photography Forensic decisions as to which pictures to take to capture the necessary details of the scene Technical aspects Cameras, lenses, film Digital vs. analog Digital technology has improved so much it soon may be the only type of photography used Lighting, sharpness, exposure

6 Cameras 5 categories Point and shoot Ease of use; no photographic training Instant (Polaroid) Ease of use; no photographic training Instant results; can retake 35 mm Some photographic knowledge Allows the photographer control over all conditions 4X5 Large format Digital Instant results; can retake Resolution Measured in megapixels The higher the number, the higher the megapixels High-resolution can be printed in large sizes without loss of clarity Memory card Digital cameras Should always back up to the computer in case something happens to the memory card or the original images Lighting The flash should be used at all times Sharpness Having the camera properly focused Most cameras focus automatically Holding the camera still Using a tripod Exposure Function of 2 separately adjustable parameters F-stop the amount of light that will be allowed to reach the film by controlling the lens opening Exposure time the amount of time the lens is open Depth of field the distance from the lens that the objects will be in focus Narrow - only objects 6-12 feet away will be in focus Wide almost everything will be in focus; used in outdoor crime scenes Forensic Aspects Selecting the correct subjects and/or objects for photographing Varies from scene to scene, but there are guidelines that must be followed Photograph the overall scene and sub-scene, going from far way to close-up and more detailed Evidence Evidence that will be collected should be photographed in its original position Markers are used to show the original position of evidence Pictures are taken with and without markers before any possible tampering can occur Used with sketches for reconstruction Impressions, tire tracks, and other evidence that cannot be collected All photographs must be labeled with the date, time, and photographer s name Video Recording Types of media used by video cameras VHS, 8mm, digital Uses of videography Monitors all people at a crime scene Acts as a security log Used as documentation to show others who were not there an overall layout of the scene Lab workers Jury

7 Narration For narration - helps the viewer understand the video record Against narration microphones are too sensitive and may pick up comments from others that are inappropriate Time stamp should be synchronized with all other watches and clocks at the scene so that all times are consistent Duty to Preserve An obligation imposed on law enforcement agencies to preserve certain audio and video recordings for a certain amount of time Original documents must be available for review by the defense attorneys May be re-examined if the case is appealed re-investigation of a case by cold case units The actual seizing and packaging of physical evidence items for submission to a forensic science laboratory in a manner that ensure integrity of the evidence, and/or documenting scene patterns that cannot be physically collected Death scene The medical examiner or coroner takes charge of the body and the items of evidence associated with it Clothes Then it is turned over for analysis in the lab Rape kits may be done postmortem and then sent to the lab Detectives often attend autopsies to find out the tentative manner of death Final manner - after all lab tests (toxicology, tissue tests) and the completion of the investigation Collection Methods Collect items intact preferred Sampling method used if it is not possible to collect the entire piece of evidence intact Evidence on the floor or other immovable objects Evidence Collection Techniques Forceps Clean, or if possible new forceps, for each new piece of evidence to be collected Sometimes the all of the evidence is collected, sometimes just a representative sample Once again, experience is very important here Tape lifting Very thorough But sometimes hard to remove the evidence from the tape Shaking, Scraping Used for evidence found on clothes Only done in a lab

8 Vacuuming Last resort It will also collect other materials that are irrelevant to the case A trace evidence examiner will have to sort through it after the vacuum is emptied Numbering and Description Evidence log Includes numbers and brief descriptions No set rules each investigator uses his or her own consistent protocol Signs/markers are used to document the original locations Use general terms Reddish-brown substance instead of blood to avoid being challenged in court Included in the package Evidence number Description Case number Time Name of collector Packaging options Paper containers Powders/hairs paper folded to form a leakproof container Secondary container to prevent any possible leakage Biological evidence paper also Non-biological evidence Ziploc bag Ziploc bag Solid evidence, except for biological Contents can be seen without opening Sealed with tamper-proof tape Some paper containers have plastic windows Paint cans For fire debris with residue that may be flammable Glass containers liquids Boxes Weapons, broken glass Controls and Comparison Standards Control to ensure that tests are working properly and to allow for comparison Types Known aka reference Blood from a known individual Known fibers from a carpet Paint from a car Alibi known same as known, but from a different source Suspected soil from an assault scene on shoes Suspect says it is from a nearby field Soil from the field is the alibi known

9 Blank Does not have the substance being tested to make sure the tests are working properly Comparison Shows that the evidence is what will give the results Unstained portion of a blood-stained carpet Lab submission Request Lists the basic case information as well as the desired tests Crime Scene Analysis and Reconstruction Lab Analysis Many labs have back-logs due to lack of funding and staff Request only the most important testing Medical Examiner Report Findings of the autopsy Toxicology report Crime Scene Analysis and Reconstruction Rules the circumstance of death Homicide Suicide Accidental Natural Undetermined If circumstance of death has been determined the cause of death will most likely be included Crime Scene Analysis and Reconstruction Reconstruction Forming a best theory of the events of a crime after the investigation is complete Reenactment Hypothetical rendition of the crime based on the reconstruction, but with all the blanks filled in