Law is a set of rules that are created and are enforceable by social
- 2. Fundamentals of Investigation Fundamentals of Investigation 1. 1. A systematic, methodical, and detailed A systematic, methodical, and detailed inquiry into the past and present inquiry into the past and present 2. 2. Corpus Delicti Corpus Delicti – elements of a crime – elements of a crime 3. 3. Act and Intent Act and Intent – the crime committed and – the crime committed and with purpose with purpose 4. 4. Degree of crime Degree of crime – what charge to file – what charge to file 5. 5. Investigation Investigation must prove each element must prove each element
- 3. Modus Operandi Modus Operandi 1. 1. Characteristic way a criminal commits a Characteristic way a criminal commits a specific crime specific crime 2. 2. Provide clues in both obvious and less Provide clues in both obvious and less obvious crimes obvious crimes 3. 3. They are beneficial They are beneficial 4. 4. Do not have decisiveness of past Do not have decisiveness of past
- 4. Two Types of Investigations Two Types of Investigations 1. 1. Preliminary investigation Preliminary investigation - - first officer on scene first officer on scene - minor crime: investigates - minor crime: investigates - major crime: secure scene - major crime: secure scene 2. 2. Follow-up investigation Follow-up investigation - - by detectives by detectives - by patrol officers - by patrol officers - - builds on what was learned builds on what was learned - during preliminary investigation - during preliminary investigation
- 5. Investigation Investigation 1. 1. Radio call to officer Radio call to officer - - time of day / weather / daylight / artificial time of day / weather / daylight / artificial lighting lighting 2. 2. Safe to enter Safe to enter - suspect - suspect not at crime scene not at crime scene 3. 3. Render first aid Render first aid - - show pathway to victim show pathway to victim - for medical professionals - for medical professionals - crime scene technicians - crime scene technicians - other volunteers - other volunteers
- 6. Investigation, cont. Investigation, cont. 4. 4. Protect scene Protect scene - - all non-essential people all non-essential people - police administrators - police administrators - the press - the press - family members - family members 5. 5. Identify witnesses Identify witnesses - - be sure to get I.D. from people that be sure to get I.D. from people that have information have information - - keep driver’s license, if necessary keep driver’s license, if necessary
- 7. Identity of Suspect Identity of Suspect 1. 1. Locate witnesses Locate witnesses - - eyewitness eyewitness - - people who saw a possible suspect people who saw a possible suspect - - saw suspect vehicle saw suspect vehicle 2. 2. Identify victim Identify victim - - contact family and friends contact family and friends - - try to find last person who saw victim try to find last person who saw victim alive alive 3. 3. Check local and state files Check local and state files - - M.O. files / computer files / fingerprints M.O. files / computer files / fingerprints
- 8. Primary Types of Evidence Primary Types of Evidence 1. 1. Direct evidence Direct evidence - - “I saw, I heard, I smelled, I tasted” “I saw, I heard, I smelled, I tasted” a. a. Includes Includes: fingerprints / DNA / ballistics / : fingerprints / DNA / ballistics / dental comparisons / handwriting samples dental comparisons / handwriting samples b. b. Testimony by expert witnesses Testimony by expert witnesses 2. 2. Circumstantial evidence Circumstantial evidence - - shoe impressions / tire tracks / types shoe impressions / tire tracks / types of of clothing / vehicle / etc. clothing / vehicle / etc.
- 9. Arrest of Suspect Arrest of Suspect 1. 1. Take into custody Take into custody (probable cause) (probable cause) 2. 2. Drive-by Drive-by: witness to identify : witness to identify 3. 3. Advise of rights Advise of rights 4. 4. Note “ Note “spontaneous spontaneous” remarks ” remarks 5. 5. Interrogation of suspect Interrogation of suspect - - confession / admission / denial confession / admission / denial
- 10. Recovery of Property Recovery of Property 1. 1. Search of suspect Search of suspect - - person / within arm’s reach person / within arm’s reach 2. 2. Search of vehicle Search of vehicle - - unlocked containers unlocked containers - - tow vehicle tow vehicle 3. 3. Search warrant Search warrant - - written waiver from owner written waiver from owner - - search warrant is best search warrant is best
- 11. Identification of Suspect Identification of Suspect 1. 1. Drive-by Drive-by - victim / witness observes - victim / witness observes 2. 2. Photo array Photo array - 6 to 8 photographs - 6 to 8 photographs - similar in appearance - similar in appearance 3. 3. Line-up Line-up - minimum: 5 / maximum: 7 - minimum: 5 / maximum: 7 - similar in build: height / weight - similar in build: height / weight - facial features / hair color - facial features / hair color