Solution Manual for Forensic Science: From the Crime Scene to the Crime Lab, 4th Edition

Chapter 2 Securing and Searching the Crime Scene CHAPTER OVERVIEW • • • • • • • • • • • The first officer arriving on the scene of a crime has the responsibility to preserve and protect the area to the greatest extent possible. First priority should be given to obtaining medical assistance for individuals in need of it. Steps must be taken by the first responder to exclude all unauthorized personnel from the scene and keep an accurate log of who enters and exits the scene and the time at which they do so. The lead investigator is responsible for developing a strategy for the systematic examination and documentation of the entire crime scene. The lead investigator must gain an overview of the general setting of the scene. Of particular importance are objects that do not appear to belong or aspects of the scene that may suggest the timing of the incident. The presence or absence of evidence may also suggest whether the scene is a primary or secondary scene. At the command center, members of the investigative team receive their assignments, store their equipment, congregate to talk about aspects of the case, and communicate with personnel at other crime scenes. How one carries out a crime-scene search will depend on the locale and size of the area, as well as on the actions of the suspect(s) and victim(s) at the scene. The purpose of the crime-scene search is to locate physical evidence. The particular circumstances of the crime determine what to search for first. When evidence is found, the location is documented in notes, photographs, and sketches. When the search is deemed complete, the investigating team conducts a final survey that includes a visual overview of all parts of the scene, an inventory of all evidence collected, the retrieval of all equipment, and the neutralization of all health or safety threats. Once all of these measures have been taken, the scene can be released to the proper authorities. LEARNING OBJECTIVES After studying this chapter, you should be able to: • Understand procedures for and importance of properly securing the crime scene. • Describe the role of the lead investigator in coordinating the crime-scene search. • Describe the conditions at the crime scene that should be given particular notice. • List and understand the various search patterns investigators can use to systematically search the crime scene for evidence. LECTURE OUTLINE SECURING THE CRIME SCENE The first officer arriving on the scene of a crime has the responsibility to preserve and protect the area to the greatest extent possible. The officer should always treat the crime scene as if the crime were still occurring until it is proven otherwise. First priority should be given to obtaining medical assistance for individuals in need of it. If needed, the officer should direct medical workers to approach the body by an indirect route to minimize the possibility of disturbing evidence. Steps must be taken by the first responder to exclude all unauthorized personnel from the scene and keep an accurate log of who enters and exits the scene and the time at which they do so. The first responder(s) are responsible for establishing boundaries of the scene to be protected. It is worth noting that personnel should never do anything while at the crime scene to include smoking, eating, drinking, or littering as this might alter the crime scene. SURVEYING THE CRIME SCENE The Walk-Through The initial survey of the scene is called the walk-through. First, the perpetrator’s path of entry and exit should be established. The investigator should follow the path made by the first responding officer to the center of the crime scene. The investigators should remember that the crime scene is three-dimensional; evidence may be found on the walls or ceilings, as well as the floor and other surfaces. • Teaching Tip: Review the questions in the book that the investigator should ask. The presence or absence of evidence may also suggest whether the scene is a primary or secondary scene. A primary scene is one at which the original incident occurred. The secondary scene is a location that became a part of the crime by activities aft the initial incident, such as using a car to transport a body. Assigning Tasks Investigators must establish a center of operations, or command center, at the scene. This is where members of the investigative team receive their assignments, store their equipment, and meet to discuss aspects of the case. At the command center, the lead investigator assigns tasks after the initial walkthrough. The tasks should be carried out in the exact order to properly process the scene. SEARCHING THE CRIME SCENE Types of Search Patterns Line/Strip Search Pattern In the line/strip search pattern, one or two investigators start at the boundary at one end of the scene and walk straight across to the other side Grid Search Pattern The grid search pattern employs two people performing line searches that originate from adjacent corners and form perpendicular lines. Spiral Search Pattern The spiral search pattern usually employs one person who moves in an inward spiral from the boundary to the center of the scene or in an outward spiral from the center to the boundary. Wheel/Ray Search Pattern The wheel/ray search pattern employs several people moving from the boundary straight toward the center of the scene (inward), or from the center straight to the boundary (outward). This method is best suited for scenes that cover large areas. Quadrant/Zone Search Pattern The qualdrant/zone search pattern involves dividing the scene into zones or quadrants, and team members are assigned to search each section Vehicle Searches If the scene includes a vehicle, the vehicle search must be carefully planned and systematically carried out. All areas of the vehicle, inside and out, should be searched with equal care for physical evidence at the scene, or the vehicle may be towed to a police department garage. Night Searches Searches during the night are especially difficult and boundaries can be very difficult to determine. When possible, the scene should be taped off, left undisturbed, and guarded until daylight; this may not always be possible. Locating Evidence The purpose of the crime scene search is to locate physical evidence. What to search for will be determined by the particular circumstances of the crime. The search ends when the team or lead investigator determines that all pertinent evidence has been located to the best of the team’s ability. When this determination is made, the team carries out a final survey of the scene. The skill of crime-scene investigators at recognizing evidence and searching relevant locations is paramount to successfully processing the crime scene. The know-how for conducting a proper crime-scene search for physical evidence is not beyond the grasp of any police department, regardless of its size. LIST OF CHANGES/TRANSITION GUIDE No major changes to this chapter. ADDITIONAL ASSIGNMENTS AND CLASS ACTIVITIES Basic Laboratory Exercises for Forensic Science Exercise 2 allows the student to apply logic and deductive reasoning to a crime scene investigation. Upon conclusion of this exercise, the student should find that Professor Kline was murdered sometime after sunset on Friday, May 11. Emily, Dr. Myers’ assistant, is the murderer. Notice the inconsistencies with the time and date of Dr. Myers’ e-mail (which she forged) and the double-occupancy charge on her hotel receipt. Demonstrations and Lecture-Starters Students should be referred to the Internet web site “Crime Scene Investigation” [http://www.crime-scene-investigator.net/ index.html]. This site provides detailed guidelines and information regarding crime scene response and the collection and preservation of physical evidence. Questions and Answers 1. List two possible consequences of failure to protect a crime scene properly. Failure to protect a crime scene properly may result in the destruction or altering of evidence, or hinder the search for the perpetrator by misleading investigators about the true facts of the incident. 2. What is the first priority of the first officer responding to a crime scene? The first priority of the first officer responding to a crime scene is obtaining medical assistance for individuals in need of it. 3. Which of these other tasks should the first officer at the scene attempt to perform? a) Sketch the scene b) Take statements from the victim c) Detain potential suspects d) Identify individuals at the scene Answer: b,c,d 4. How should medical workers approach a body at a crime scene? Why? Medical workers should approach a body at a crime scene by an indirect route to minimize the possibility of disturbing evidence. 5. Describe three steps investigators typically take to control access to a crime scene. Three steps investigators typically take to control access to a crime scene include establishing the boundaries of the scene, preventing unauthorized access to the crime scene, and keeping an accurate log of everyone who enters or leaves the scene. 6. Which are more difficult to determine: the boundaries of an indoor crime scene or those of an outdoor crime scene? Explain your answer. The boundaries of an outdoor crime scene are usually more difficult to determine because they can cover a much greater area than indoor crime scenes. 7. What is a walkthrough? What is the first step in this process? A walkthrough is the initial survey of the crime scene. The first step in a walkthrough is to establish the perpetrator’s path of entry and exit. 8. What does an investigator do with pieces of evidence he or she discovers at a crime scene? The investigator must document and photograph any evidence found at the crime scene. 9. How does the investigator treat fragile evidence found at the crime scene? The investigator may secure fragile evidence or tagged it for a search team. 10. What is the difference between a primary and a secondary scene? A primary scene is one at which the original incident occurred. A secondary scene is a location that became part of a crime by activities that occurred after the initial incident. 11. Describe the basic functions of a command center. What kind of equipment must a command center contain? A command center serves as a place where members of the investigative team receive their assignments, store their equipment, and meet to talk discuss aspects of the case. The command center can also be a center for communication between investigators at multiple crime scenes. The command center must contain the basic equipment needed to photograph, sketch, process, and collect evidence. 12. List the basic tasks performed by investigation teams after the walkthrough, in the order needed to properly process the scene. The basic tasks needed to process a crime scene include locating possible evidence, assessing the evidence, processing evidence, and photographing and sketching the scene. 13. Name three factors that determine how one carries out a crime-scene search. How one carries out a crime-scene search depends on the locale, the size of the area, and the actions of the suspect(s) and victim(s) at the scene. 14. Which of the following search patterns can be performed effectively by one person? a) Grid b) Line c) Quadrant d) Spiral Answer: b,d 15. Which search pattern is best suited for searching a large area? Describe this search pattern. The quadrant or zone pattern is best suited for scenes that cover a large area. 16. When searching a vehicle, what surfaces must investigators be careful to avoid contacting? Give two common examples of such surfaces. When searching a vehicle, an investigator must avoid touching surfaces that may contain fingerprints. Common examples of such surfaces include a steering wheel or a door handle. 17. What kind of evidence do investigators particularly look for when searching a vehicle involved in a hit-and-run case? In a hit-and-run case, investigators pay particular attention to looking for any evidence resulting from a cross-transfer of evidence between the car and the victim. 18. What is the best procedure to follow when a nighttime crime scene is too dark to search properly? What steps should an investigator take if circumstances do not permit this procedure? If a scene is too dark to search properly, the scene should be taped off, left undisturbed and guarded until daylight can be used. If circumstances do not allow waiting until daylight, a perimeter must be estimated and floodlights should be set up prior to the search. 19. In the case of homicide, where will the investigator’s search be centered? In the case of homicide, the investigator’s search will be centered on the weapon and any type of evidence left as a result of contact between the victim and the assailant. 20. When does the crime scene search officially end? The search ends when the team or lead investigator determines that all pertinent evidence has been located to the best of the team’s ability. 21. Describe the steps the crime scene investigation team takes during its final survey of the crime scene. During its final survey of the scene, the team makes a visual overview of all parts of the scene, takes an inventory of all evidence collected so nothing is lost or left behind, retrieves all equipment, and verifies that any threats to health or safety at the scene have been or will be dealt with properly.