Lesson 1 Crime Scene Investigation
Case Reading 1 A woman was killed in a “robbery”. • A man called 999 that his wife was killed by a robber and he suffered from 2 gunshot wounds (one at his left arm and the other at his left thigh) at 11 o’clock at night while they were walking along the beach.
Activity 1.1 General Crime Scene Procedure Suppose you were the senior police officer who would take charge of the crime scene investigation upon receiving the 999 call. What would be the general crime scene procedure? Instruction: • Divide yourselves into groups of 4 students. You would have 15 min. for group discussion. • Group presentation: 10 min.
Activity 1.1 General Crime Scene Procedure • To assist/help/protect the victim if he/she is still alive by carrying out first aid and/or calling the ambulance; • To assess the crime scene; • To seal the crime scene – it helps preserve important forensic evidence and identify potential suspect(s)/witnesses by eliminating the possibility of people leaving or entering the crime scene before the completion of the crime scene investigation;
Activity 1.1 General Crime Scene Procedure • To detain the potential witnesses and suspects and remove them from the crime scene to be questioned separately or even searched by police officers if necessary;
Activity 1.1 General Crime Scene Procedure • To identify the crime and categorize the crime into burglary, robbery, arson, murder, kidnap, sexual assault, etc.; • To document the crime scene-the forensic photographers help record the crime scene by means of cameras, digital cameras and video cameras;
Activity 1.1 General Crime Scene Procedure • To search for evidence; • To do forensic analysis in the laboratory;and • To reconstruct the crime scene (at a later stage).
Activity 1.1 General Crime Scene Procedure Questions (a) Why do police officers usually question potential suspects/witnesses separately? (b) It is suggested that it is not good to collect too much or too little evidence. Please comment.
Activity 1.1 General Crime Scene Procedure Suggested Answers (a) To prevent the witnesses discussing what they each saw and prevent one’s recall of the incident being influenced by the ideas of others
Activity 1.1 General Crime Scene Procedure Suggested Answers (b) It is not cost effective to collect irrelevant evidence. However, if we collect too little evidence, some important forensic evidence may be missing which in turn would affect the crime investigation. Experience in collecting forensic evidence may help solve this problem. However, one should always note that minor evidence may contribute much to solve the crime case.
Activity 1.2 Crime Scene Search After crime scene documentation (taking notes, videos and photos) is completed, the crime scene is searched for more physical evidence There are some searching patterns commonly used by the police:
Activity 1.2 Crime Scene Search (a) Chose a search pattern for your group and look for some missing objects (not related to the said crime) within 5 min. (b) What are the pros and cons of your searching pattern in looking for forensic evidence?
Remarks: If necessary, the practical application of the search methods to a crime scene may be a combination of different methods.
Activity 1.3 (Secure a Crime Scene) Referring to the Crime Scene Photos and the Crime Scene Sketch in worksheet 1.3 (a) establish a perimeter to secure the crime scene. The perimeter is delineated by “police barricade tape” with words “POLICE CORDON DO NOT CROSS” (警察封鎖線 不得越過)
Activity 1.3 (Secure a Crime Scene) (b) Place numbered evidence markers to show the location of the pistol (a pistol was found 50 m from the dead body near the rocks), dead body, etc. at the crime scene.
Activity 1.3 (Secure a Crime Scene) Suppose you were required to search the above crime scene for any physical evidence. (a) How would you do the searching? Explain why you choose such search option. (b) What important information is missing in the given crime scene sketch?
Activity 1.3 (Secure a Crime Scene) Answer to (a) • It depends on the environment, crime cases and manpower, etc. Answer to (b) • Missing elements are the time, description of the crime and the measurements of the crime scene.
Activity 1.4 Collection of Forensic Evidence (a) What information and /or forensic evidence you would like to obtain/collect for testing in the forensic laboratory regarding this crime case?
Evidence Collection Kit http://store.sirchie.com/SEARCH-3-DrawerStorage-Evidence-Collection-Kit-P1676C468.aspx
Suggested answer: (a) • Oral confession of the husband, local residents at region I and passersby along the Silverstrand Beach Road; • Autopsy report; and • Forensic evidence collected (e.g. fingerprint, footprint, blood spatter pattern and DNA evidence).
Activity 1.4 Collection of Forensic Evidence (b) Tell your teacher what sorts of information and/or forensic testing result you need. Then get the relevant information sheets from your teacher if he/she has got them.
Activity 1.5 Crime Scene Reconstruction (a) Based on the information you gathered and the forensic evidence try to (i) evaluate the forensic evidence and the credibility of the oral confession of the and (ii) RECONSTRUCT the above crime scene. (b) Presentation (c) What are the limitations to reconstruct a crime scene?
Activity 1.5 Crime Scene Reconstruction • Importance of striving for objectivity-it is suggested that the forensic evidence needs to be evaluated by several individuals throughout the crime scene investigation. • Crime scene reconstruction personnel should avoid trying to prove any theory or hypothesis but should use the processes of deductive reasoning, inductive reasoning and falsifiability to create a logical reconstruction of the crime case.
References: • Siegel, J.A. (2007). Forensic Science: The Basics. Florida: CRC Press. • Saferstein, R. (2009). Forensic Science: From the Crime Scene to the Crime Lab. New Jersey: Pearson Education, Inc.