Crime Scene Procedures
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Crime Scene Procedures Introduction Derek Walker 4th year Forensic Science Student University of Ontario Institute of Technology (UOIT) Bachelor of Science (Hons) Minors in Biology and Chemistry Research experience: Forensic Psychology (eyewitness identification) Microbiology CCSS graduate What is Forensic Science? Forensic: “pertaining to legal matters” Science: “the systematic organization of knowledge through the experimental testing of hypotheses for the purpose of explaining phenomena in our universe” Essentially, “The Scientific Method” Forensic Science: “The application of the Scientific Method to legal matters” Forensic Science encompasses a wide variety of disciplines Disciplines of Forensic Science Physiological Social Sciences Criminalistics Digital Physical pathology psychology ballistics computers accident reconstruction anthropology psychiatry dactology databases physics entomology toxicology networks engineering biology document analysis mobile devices fire investigation chemistry video botany audio Personnel Involved in Investigations of Crime First responders Crime scene investigators Forensic Identification Officer Scene of Crime Officer (SOCO) Forensic Typically experts in a specific discipline Coroner Scientists (Medical Examiner) In Ontario, all are physicians Forensic Pathologist Homicide Investigations If death appears suspicious First Responders Coordination of crime scene investigation Forensic Identification Officer SOCO Forensic Scientists Many police services don’t have the resources to analyze all types of evidence, so it is outsourced Police officers, EMS, firefighters Homicide Determines manner of death, issues death certificates, recommends how to prevent similar deaths Coroner Some scenes require experts to collect evidence or provide analysis Body goes to autopsy after being documented Coroner and pathologist communicate to report cause and manner of death Forensic Pathologist Crime Labs, other external agencies Other Types of Investigations Office of the Fire Marshal Investigate major fire scenes Special Investigate scenes where police have caused serious injury Ministry Investigations Unit of Labour Investigate industrial and farming deaths Crime Scene Investigation Misconceptions Clip from Superbad Crime Scene Investigation Misconceptions – The CSI Factor Don’t drive hummers Don’t wear Prada to crime scenes Don’t wear high heels to crime scenes Don’t utter cheesy one-liners like Horatio at the start of every investigation Don’t find fingerprint or DNA matches in minutes Don’t investigate in the dark Crime Scene Management Preserves the integrity of evidence to ensure that it is admissible in court Initial response: Preservation of life if possible Isolate suspects and witnesses Protect the scene Record scene details i.e. time, date, personnel and persons present Initial Response First priority is always to assist a victim who is still alive Limit Be access to scene aware of possible evidence Scene Protection Video http://www.youtube.com/watch?v=5LbV9l 9d2Cw Scene Protection Establish a perimeter that appears to encompass scene in its entirety Block off boundaries Physical presence of police and crime scene tape Remove unnecessary personnel Chose a “path of contamination” and avoid walking around aimlessly Scene Continuity Locard’s Exchange Principle: “Every contact leaves a trace” Must ensure not to deposit foreign objects, or take away any objects from the crime scene Starts with personal protective equipment (PPE) PPE Investigative Teams Crime scene investigation is a team effort Searching usually requires at least 2 people, but can be a lot more if the scene is bigger 2-3 people for photography 2-3 people for sketches and measurements 2-3 people for collection of evidence 1 person to take notes Scene Examination Durham Regional Police Services Forensic Identification Unit uses LOSER principle Listen to victims/witnesses Observe the scene Search victims and scene for evidence Evaluate if evidence adds up to statements Record the scene Scene Observation Helps to choose a path which will prevent any unnecessary contamination Allows you to see where the body is located within the scene Can give a general idea of where to look for evidence Allows you to judge which type of search method is best for the scene Scene Search Should be done in a systematic and controlled manner Begin with an initial walkthrough Note location of evidence so that you can return to collect it later Method of scene search will depend on number of CSI’s and size/type of scene Search Methods There are 4 general types of searches: Spiral Strip Grid Zone Some methods are more effective for different types of scenes Spiral Search Start in the middle of an area, and spiral outward/inward in a clockwise/counterclockwise direction Effective in small interior rooms Strip Search CSI’s begin at one end of search area standing directly beside each other, and walk (or crawl) toward the opposite end of the search area Advantageous for large outdoor scenes Grid Search CSI’s begin at one end of search area, and proceed to other end in a straight line Done once again except same area is searched perpendicularly to initial search direction Advantageous because the same area is searched twice Zone Search Search area broken down into zones, and each zone is searched separately Useful in small confined spaces Types of Evidence Common types of evidence: Fingerprints Footwear impressions Firearms, weapons and toolmarks Trace evidence Biological evidence Search Tools Oblique lighting Chemical reagents Angled light that causes shadows of trace evidence to become more visible Phenolphthalein (Kastle-Meyer test) Luminol Polilight Different wavelengths of light can cause certain invisible biological specimens to fluoresce Polilight Polilight Video http://www.youtube.com/watch?v=QoyRe nZMldE&feature=related Luminol Reacts with oxidizing iron present in hemoglobin to produce a strong blue chemiluminescene Can detect trace amounts of blood that may not be visible to naked eye Can show if there is evidence of an attempted clean up Doesn’t react specifically with blood Luminol Video http://www.youtube.com/watch?v=J6Lr83J gp_I&feature=results_main&playnext=1&list= PLC8565883057111BC Luminol Phenolphthalein Indicator used in Kastle-Meyer test as a presumptive test for blood Reacts with hemoglobin which has peroxidase-like activity Can detect very small amounts of blood Can react with natural produced vegetable peroxidases Found in broccoli, cauliflower, horseradish Scene Documentation Most important part of investigation When case eventually goes to court, must be able to account for all evidence, its exact location in the scene, and who has been involved in the investigation Different types of scene documentation: Photography Measurements Evidence General notes and logs Sketches Crime Scene Photography Evidence and scene are photographed as it is found Provides accurate visual descriptions for future analysis by investigators, attorneys, judges/juries Shows that evidence hasn’t been altered or tampered with between collection, and as an exhibit in court Gives context of scene, and shows areas of interest Take overall, mid-range, and close-up photographs Crime Scene Photography Overall shots Mid-range shots Intend to show as much of scene or area of interest as possible Focus on an area of interest Includes objects that are also found in overall shots Used to establish location of close-ups Close-up shots Taken using macro lens Show detail of evidence Take shots with and without scale Film plane must be perpendicular to object Crime Scene Measurements Used to visualize the exact position of evidence/objects in the scene Also to visualize where windows, doors and points of entry are located in relation to evidence/objects Allows reconstruction of scene at a later date Measurements must be very precise Made with tape-measures, rulers, laser, etc. Movable objects measured to points of reference Usually immovable objects or landmarks Evidence Collection Depends on type of evidence being collected Packaged in a manner that ensures continuity of evidence Some evidence can be damaged by the method of packaging Most fragile or weather dependent evidence collected first Chain of Custody is started upon collection Notes and Logs Meticulous notes are key to any investigation Forces investigators to commit observations to writing Corroborates statements Refreshes memory Detailed narration of all actions taken at the crime scene in chronological order Notes and Logs What to include in notes: Date and time Location of scene Description of scene and surrounding area Who requested investigation Names of officers, investigators, emergency personnel, witnesses, suspects, detainees Name of investigators associated with tasks they were responsible for (photographer, sketcher, etc.) Weather, lighting conditions Location and description of evidence, and who collected it Notes and Logs Logs to catalogue all photographs, measurements and evidence Crime Scene Sketches Supplement reports and photographs Photos don’t always depict exact location of objects or their relation to other objects Photographs can sometimes be deceiving due to perspective or distortion Excellent visual aid for juries in court Two phases of sketches Rough sketch Finished/Formal sketch Crime Scene Sketches Rough sketch Done free-hand at scene Never replaced by finished sketch and is considered evidence as well Often compared to finished sketch in court Crime Scene Sketches Finished sketch Correct any mistakes in rough sketch Presents clean, clear diagram of scene with scaled measurements included UOIT Crime Scene House UOIT Crime Scene House Stage mock crimes and use forensic investigative methods to “solve” crimes In 2nd year, learn basic investigative techniques Dusting for fingerprints, taking toolmark and footwear impression casts, collect biological evidence, collect trace evidence (paint, glass, powders) In 3rd year, apply investigative techniques to full investigations such as a hit and run, a shooting case, a sexual assault, a homicide, and a suspicious death Need to document really well, because one of these cases goes to mock court! UOIT Forensic Science Program Strong Lots base in Biology and Chemistry of lab work Mini-research Opportunity projects to do honours thesis project with internal or external supervisors UOIT Forensic Science Program - Courses 1st year General courses: biology, chemistry, physics, calculus, computers, introduction to forensic science 2nd year Organic chemistry, cell biology, physiology, anatomy, genetics and molecular biology, biochemistry, statistics and probabilities, introductory psychology UOIT Forensic Science Program - Courses 3rd year – forensic biology, forensic chemistry, analytical chemistry, instrumental analytical chemistry, physical chemistry, principles of pharmacology and toxicology 4th year – forensic drug chemistry and toxicology, interdisciplinary topics in forensic science, law for forensic scientists, forensic psychology, forensic physics* Plus electives UOIT Forensic Science Program Intimate classroom sizes Hands-on experience with instruments used in the field Prepared very well for work force Different types of research currently underway Decomposition chemistry, forensic entomology, forensic microbiology, computer-based blood spatter analysis Questions? derek.walker@mycampus.uoit.ca Or Laura Benninger – Forensic Science Program Director laura.benninger@uoit.ca
