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Crime Scene Investigation

Crime Scene Investigation

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Crime Scene Investigation

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  1. Crime Scene Investigation

  2. Crime SceneInvestigation Scenario • Police have been called to a one-room apartment to investigate a possible homicide. The body is on the floor near the center of the room with what appears to be a single gunshot to the head. The suspected weapon is lying nearby. • Describe how you would go about investigating this scene, with particular reference to establishing the integrity of the crime scene, safety and contamination of any evidence.

  3. Crime Scene Investigation • Principles of Crime Scene Investigation • Preserving the Integrity of the Crime Scene • Recording the Crime Scene • Searching the Scene • Collecting & Packaging of Evidence • Crime Scene Safety • The most important aspects of CSI work include: Securing the scene • Prevention of contamination • Preservation of physical evidence

  4. Crime SceneInvestigation The Crime Scene Environment Crime Scene Investigators (CSIs) interact with: • Police officers (including general duties, investigative, specialist and administrative areas Some CSIs are police officers/some are civilian) • The judicial system including: legal practitioner, (prosecution and defense lawyers) judges and courts (including civil, coronial, criminal and appeal Courts) • Forensic scientists (including specialist laboratories and experts)

  5. Crime SceneInvestigation • Forensic medical practitioners (including pathologists, psychologists and psychiatrists) • General community often represented through juries, including those involved in specific incidents (victims, suspects, witnesses) and expectations shaped by media reporting of actual cases, fictional material, (books, magazines, television and movies).

  6. Crime SceneInvestigation Role of the Crime Scene Investigator • Establish clear and direct lines of communication and be effective managers: • At the scene of the crime or incident • Of the processing of physical evidence collected from the scene • Of the investigative process as it relates to physical evidence • Of the final presentation of physical evidence at court

  7. Crime SceneInvestigation When investigating, the CSI should consider: • Use an entry other than that taken by the suspect • Establish the path taken by other persons first on the scene • Consider the loss of trace evidence on entry throughout your examination, (e.g.. shoe/foot impressions on the floor)

  8. Crime SceneInvestigation • Reassess Occupational Safety and Health (OSHA) issues • Establish the extent of the scene and additional assistance that may be required • Establish an entry and exit path for the Senior Investigating Officer and specialists to access the scene, if necessary

  9. Crime SceneInvestigation Boundaries usually start at the focal point of the scene and extend outward to include:  • Where the crime occurred • Potential points of entry and exit of suspects and witnesses • Places where the victim or evidence may have been moved

  10. Crime SceneInvestigation The basic protocol for scene processing can be summarized as several sequenced tasks: • Survey the crime scene • Photograph the crime scene • Map and measuring the crime scene • Record and document the location of physical evidence at the crime scene • Searching for fingerprints and other physical evidence. *During the walk-through, a walkway other than the established path of entry should be used to reduce contamination. 

  11. Crime SceneInvestigation There are generally 6 important categories of documentation that are applicable to any search: • Administrative Worksheet • Narrative Description • Photographic Log – overview, specifics • Diagram/Sketch – scaled sketch • Evidence Recovery Log - Identify, Collect and Preserve evidence  • Latent Print Lift Log

  12. Crime SceneInvestigation Approach to Searching • Consider the nature of physical evidence and the principles of exchange and transfer. (Locard) • Each scene is unique and must be approached with an open mind.

  13. Crime SceneInvestigation • The most transient evidence should always be collected first, progressing to the least transient evidence. • Moving from the least intrusive collection techniques to the most intrusive techniques.

  14. Crime SceneInvestigation • The collection of evidence must be documented, by recording its location at the scene, the date of collection and who collected it. • For each item collected, a chain of custody must be established. 

  15. Crime SceneInvestigation List of evidence collection guidelines for: • Bloodstains • Seminal stains • Hair • Fibers • Glass • Paint • Flammable liquids • Firearms evidence • Tool marks • Controlled substances & medicinal preparations • Questioned documents • Latent fingerprints

  16. Crime SceneInvestigation 3 Methods to adopt in your approach to searching • Positive Approach – what is there • Negative Approach – what isn’t there • Information/Intelligence

  17. Crime SceneInvestigation • The positive search which centers on known facts to locate evidence which is expected to be found (the tool mark in the scenario) • The negative search, which centers on known facts to indicate that no evidence, was found to indicate an alternate explanation (e.g. could the suspect have entered through another door)

  18. Crime SceneInvestigation • The intelligent search which requires a combination of known facts, consideration for other explanations and a systematic and thorough approach to locate any other evidence (finding of the tip of the pliers, based on information about a pair of pliers)

  19. Crime SceneInvestigation Searching Patterns or Methods • There are 5 basic methods that are universally accepted. These are: • Line/Strip method • Spiral method • Wheel/Ray method • Grid method • Quadrant/Zone method

  20. Crime SceneInvestigation

  21. Crime SceneInvestigation • Line/Strip Search Pattern --One or two investigators start at the boundary of the crime scene and search in straight lines across to the other side of the crime scene. • Grid Search Pattern -- Two or more investigators form a grid by searching in line patterns that overlap and are perpendicular to each other.

  22. Crime SceneInvestigation • Spiral Search Pattern --One investigators searches in a spiral path from the center of the crime scene to the boundary (outward) or from the boundary of the crime scene to the center (inward). • Wheel/Ray Search Pattern --Several investigators search in straight lines from the center to the boundary (outward) or from the boundary to the center (inward). • Quadrant/Zone Search Pattern --The crime scene is divided into smaller sections (zones). One or more investigators are assigned to search each zone.

  23. Crime SceneInvestigation The area(s) to be searched will often be determined by the: • Nature of the incident • Nature of the physical evidence present • Location • Terrain • Established facts

  24. Crime SceneInvestigation The Golden Rules of a Search 3 Golden Rules to maximize the recovery of evidence: 1. Search areas should be determined to maximize concentration. Each area should take no more than 20-40 minutes to search. 2. Breaks should be taken after each search. (At least 10 minutes) 3. Search the same area twice so that nothing is overlooked

  25. Crime SceneInvestigation Legal Considerations Regarding Evidence Circumstances where the police can search for evidence in the absence of a search warrant: 1. Emergency circumstances 2. To prevent loss or destruction of evidence 3. A search of a person and property in immediate control of the person as long as it is in the event of a lawful arrest 4. A search made under consent of the party involved

  26. Crime SceneInvestigation Purpose of an CSI examination is to: 1. Locate and identify potential evidence 2. Provide information about the crime or incident 3. Assist in the corroboration or otherwise of information provided by suspects, victims or witnesses

  27. Crime SceneInvestigation Type and Scale of Examination Determined by: 1. Seriousness of the offence/incident, type of the offence/incident and relevant circumstances 2. The nature of the scene

  28. Crime SceneInvestigation Before examining evidence, which involves moving, or disturbing it, the following should be checked: 1. Ensure appropriate OSHA requirements been followed (e.g. bio hazards procedures) 2. Has the area or item to be examined been photographed in place? 3. Ensure adequate notes, sketches and measurements of the area or item have been taken? 4. If the area or item is to be moved or disturbed during the examination, ensure that evidence will not be contaminated or destroyed?

  29. Crime SceneInvestigation Prioritize the collection of evidence to prevent loss of, or damage to, an item. Smaller items or evidence are usually prone to damage. Generally: • Ensure fragile evidence is collected first e.g. latent fingerprints • Then collect trace evidence e.g. blood and fiber • Finally, collect larger items

  30. Crime SceneInvestigation Cross Contamination and Biological Degradation • Prevent cross contamination and/or biological degradation. When collecting an item from the scene care must be taken to ensure that it is collected in a way, which will preserve (as closely as possible) its original condition.

  31. Crime SceneInvestigation Labeling At the time of collection: - a detailed label should be attached to the package and include all of the following: • Time & date collected • By whom collected • Type of incident • Description of the item • Location of the incident • Suspect & victims name if known • Location of the item • Name of the Senior CSI & their location • CSIs – names and job number

  32. Crime SceneInvestigation Continuity is maintained by: • Accurate records (of the scene and item) • Detailed labeling, appropriate and sealed packaging • Accurate official records and logs • Secure storage of the item(s) • Full documentation of any subsequent movement • It is preferable that the CSI is the only link in the chain of custody of an item

  33. Crime SceneInvestigation Interpretation may include: • Assist in establishing how the incident occurred • Prove or disprove witness, suspect or victims, versions of the incident • Provide investigators with information, which may assist with inquiries and interviewing of witnesses, victims, and suspects

  34. Crime SceneInvestigation Suitable evidence is used in court. Interpretation may suggest a theory of what occurred, based on: • Observations at the crime or incident scene • The physical evidence located • Information received from the Senior Investigating Officer e.g. interviews and subsequent inquiries • Results of examinations, analyses and other specialized tests.

  35. Crime SceneInvestigation • The results of interpretation are the formation of opinions or likely conclusions • Interpretation must be thorough and a reliable report made of the observations, rather than the investigator's belief of what occurred.

  36. Crime SceneInvestigation 4 Basic Limitations to the process of Reconstructingthe incident: • Quantity and quality of the information received, physical evidence present and method of recording. 2. Ability and expertise of the crime scene investigator. 3. Extent of interpretation required. 4. Time and financial resources available.

  37. Crime SceneInvestigation Human Remains and Identification Notes should include: • Position of the body • Description and state of clothing (is it partially removed, stained, tangled or twisted?) • Describe the location, intensity, size, and direction of flow of any staining if possible. • Type of stain (blood-like, semen, dirt, vomit, feces, urine or some other fluid)

  38. Crime SceneInvestigation • Any visible damage to the clothing and body • Description of bloodstains (spots, spatter or smearing and directionality) • Appearance of evidence removal (has the body been washed or blood cleaned from the body?) • Estimated amounts of blood (has staining penetrated layers, carpeting or other surfaces, is it superficial?)

  39. Crime SceneInvestigation The Recovery Of Human Remains • Outdoor vs. Indoor • Decomposition Rates/Temp. 3.Use of Dogs to find bodies (9/11)

  40. Crime SceneInvestigation Forensic Specialties Anthropology • The scientific discipline mainly concerned with the study of bodily or skeletal remains. • DNA, Mitochondrial DNA (family) • Dr. Michael Baden/[ ]

  41. Crime SceneInvestigation Its possible to determine 2 types of information from remains: • Physical characteristics such as sex, ethnicity, approximate age, stature, certain disease states and old injuries • The actual identification of the individual

  42. Crime SceneInvestigation Forensic Odontology • Uses dental records to help in human identification, and is often necessary for the identification of unrecognizable bodies, after fires or mass disasters, and in the identification and comparison of bite marks.

  43. Crime SceneInvestigation Forensic Pathology Estimating Time of Death • Changes in appearance of eyes • Cooling of Body Temperature (livor mortis) • Rigidity of the body (rigor mortis) • Blood pooling in a specific area of the body (algor mortis) 5.Decomposition or putrefaction is the breakdown of the body due to autolysis and bacterial decomposition 6. Insect Infestation and Forensic Entomology

  44. Crime SceneInvestigation Forensic Photography • Crime scene photographs are permanent and comprehensive pieces of evidence that may be presented in court to prove or disprove facts in question.

  45. Crime SceneInvestigation Blood Splatter Analysis -Bloodstain Interpretation • Properly collected and preserved blood evidence can establish a link between an individual, a criminal act or a crime scene • It is used to strengthen or contradict a witness or suspects statement or to eliminate a person as a potential suspect in a crime.

  46. Crime SceneInvestigation Blood Splatter Analysis Expert • 1971 • MacDonell (AFIP, Washington, DC) • Outlined general rules regarding blood spatter evidence • Outlined general rules of blood spatter pattern recognition including spot shape, edge characteristics, spot diameter, angle of impact, degree of spatter, directionality, cast off droplets and high and low velocity impact stains

  47. Crime SceneInvestigation Collecting Blood Evidence • Collection and Preservation of Blood Evidence  • Dried Bloodstains  • Wet Bloodstains •

  48. Crime SceneInvestigation Wet Blood Stains • Liquid pools - pick up on gauze pad or other clean, sterile cotton cloth. Allowed to air dry thoroughly at room temp. Refrigerate or freeze as soon as possible. Delays beyond 48 hours may make blood samples useless. • Deliver stained object immediately to lab. • If the object must be mailed, allow the stain to air dry completely before packaging. • Do not heat stained material or place it in bright sunlight to dry. Hang clothing and similar articles in a room where there is adequate ventilation. • If not completely dry, label and roll in paper or place in a brown paper bag or box and seal and label container. Place only one item in each container. Do not use plastic containers.

  49. Crime SceneInvestigation Dried Blood Stains • On clothing, wrap the item in clean paper, place the article in a brown paper bag or box and seal and label container. • Small solid objects: send the whole stained object to the Lab. • Large solid objects: cover the stained area with clean paper and seal the edges down with tape to prevent loss or contamination. If impractical to deliver the whole object to the Lab, scrape the stain onto a clean piece of paper, which can be folded and placed in an envelope. Scrape blood from objects using a freshly washed and dried knife or similar tool. Wash and dry the tool before each stain is scraped off. Seal and mark the envelope. • Do not mix dried stains. Place each stain in a separate envelope. • Do not attempt to wipe dried stains from an object using a moistened cloth or paper.

  50. Crime SceneInvestigation Motor Vehicle Investigation