CHAPTER 3 (48) THE INVESTIGATIVE METHOD

STARTING POINTS 1. State the problem 2. Form the hypothesis 3. Observe and experiment 4. Interpret the data 5. Draw conclusions

INVESTIGATIVE ACTIONS STATE THE PROBLEM Who, what, when, where, why, how FORM THE HYPOTHESIS Establish Motive, Means, Opportunity OBSERVE AND EXPERIMENT Evaluate hypothesis, reject if needed Interpret results Identify suspect

INVESTIGATIVE ACTIONS (Cont.) DRAW CONCLUSIONS Stated problem answered Evidence support of hypothesis Ethics considerations Evidence adequate for prosecution EFFECT ARREST, RECOVER PROPERTY

EVIDENCE/HYPOTHESIS ALWAYS LET YOUR EVIDENCE DEIVE YOUR HYPOTHESIS!!!!! YOUR HYPOTHESIS MUST CHANGE WHEN EVIDENCE SUPPORTS THE CHANGE!!!!! THE HYPOTHESIS MUST NEVER DRIVE THE INVESTIGATION!!!!!

HYPOTHESIS Construct an explanation for occurrence Why this type and particular target? How knew locations of valuables? WHO HAD MOTIVE, MEANS, AND OPPORTUNITY?

MOTIVE That which causes a person to act in a certain way. Monetary gain is the most likely. Murder: Ask who would benefit. Arson: Ask who would benefit.

MEANS Capability of committing the crime Who has the tools? Who has the knowledge?

OPPORTUNITY Who was present that could have committed the crime? What was the victim doing that could have put him/her into contact with the offender? Suspect out of town or in jail Suspect has an alibi

OTHER PHASES Observation and experimentation Testing hypotheses Interpreting data ALL THESE ARE SIMULTANEOUSLY WITH THE OTHER PHASES PUZZLE-Number of pieces? Lack of pieces? Final picture?

GUILTY OR NOT Inculpatory evidence serves to prove guilt Exculpatory evidence clears or exonerates

LEGAL GUIDELINES Evidence- Anything properly admissible in court that will aid the function of a criminal proceeding in establishing guilt. Admissible means that it can be legally used in court. Inadmissible means that it cannot be legally used in court

CIRCUMSTANTIAL The more physical evidence the better. –You never have all you need –If there is anything else, get it.

TYPES OF EVIDENCE DIRECT EVIDENCE Will normally prove a fact without other support. Testimonial INDIRECT EVIDENCE All physical evidence is CIRCUMSTANTIAL. It puts the suspect at the crime scene. It does not prove guilt in itself.

PHYSICAL EVIDENCE Real evidence, physical, tangible items May be trace evidence- forensic, needs analysis Fingerprints Hairs Fibers Blood DNA- Deoxyribonucleic acid

SUITABILITY EVIDENCE MUSTBE COMPETENT Has qualities that make it trustworthy or reliable. Question who is reliable? RELEVANT Relates directly to the case MATERIAL Logical connection and helps find truth

EXCLUSIONARY RULE Illegally obtained evidence cannot be used in court. Applies to violations of Constitutional rights Weeks v. US Mapp v. Ohio

EXCEPTIONS HEARSAY Confessions to an investigator Dying declarations Res Gestae statements Judicial notice Testimony of a female under 14 yr. who is a victim of a sex crime

RULE OF DISCOVERY Allows the defendant, through his attorney, to examined documents, reports and other information in possession of the police or prosecution Prosecution must give up everything Lose your case in a suppression hearing

PROBABLE CAUSE 4 th Amendment ARREST- A reasonable person would believe that a crime has or will be committed and the person to be arrested committed or will commit the crime. SEARCH- A reasonable person would believe that a crime has or will be committed and evidence of the crime will be found in the place to be searched

SEARCH WARRANT THREE PARTS AFFIDAVIT WARRANT RETURN

EXCEPTIONS REQUIRES SAME PROBABLE CAUSE WARRANTLESS SEARCH IS UNCONSTITUTIONAL ON ITS FACE

EXCEPTIONS Exigent circumstancesExigent circumstances Stop and frisk Search incident to arrestSearch incident to arrest Custodial Plain view Vehicle Border Open fields Abandoned property Consent Administrative Probation search Protective sweep

BURDEN OF PROOF CRIMINAL CASE- Beyond a reasonable doubt- continuous demonstration of guilt 99+ percent sure CIVIL CASE- A preponderance of the evidence- whoever has the best case 50+ percent sure

CORPUS DELICTI “BODY OF THE CRIME”- The fact necessary to prove that a crime was committed. All the essential ELEMENTS of an offense constitute the “corpus delicti” Investigator must know all the elements of every crime and be able to prove each beyond a reasonable doubt

PHASES OF CRIMINAL INVESTIGATION PRELIMINARY INVESTIGATION IN-DEPTH INVESTIGATION CONCLUDING INVESTIGATION

PRELIMINARY Offense determined Suspect arrest if he is on scene Protect crime scene Victims and witnesses identified Basic statements taken Crime scene processed- by investigator

IN-DEPTH INVESTIGATION Preliminary inv. Data re-examined Crime scene re- visited Additional crime scene processed- May need to get another search warrant All victims and witnesses interviewed Documents processed Facts and evidence gathered Criminalistics arranged- forensic work

CONCLUDING INVESTIGATION Case is suspended Case is prepared for prosecution

CLEARANCE RATES VIOLENT CRIMES Murder 61% Aggravated assault 54% Forcible Rape 41% Robbery 25%

CLEARANCE RATES PROPERTY CRIMES Burglary 13% Larceny-theft 17% Motor vehicle theft 13% Arson 17%

SUCCESSFUL INVESTIGATIONS 1. Are there witnesses? 2. Is there a suspect? 3. Can police locate the suspect? 4. Is there a description (photo)? 5. Can police make identification? 6. Can a suspect vehicle be identified? 7. Is stolen property traceable?

SUCCESSFUL INVESTIGATION 8. Is there a clear modus operandi (MO)? 9. Is there significant physical evidence? 10. Is there a positive report of physical evidence by a trained investigator? 11. Is it reasonable to expect the case to be cleared? 12. Is it likely that anyone but the suspect committed the crime?

IN-DEPTH/ CONCLUDING INVESTIGATION SEE P. 62 IN TEXT FOR ACTIVITIES OF THE IN-DEPTH INVESTIGATION SEE P. 63 IN TEXT FOR ACTIVITIES OF THE CONCLUDING INVESTIGATION

ARREST/ PROSECUTION SEE P.64 FOR THE TYPICAL OUTCOME OF 100 FELONY CRIME INVESTIGATIONS

SEARCH WARRANT SEE SEARCH WARRANT EXAMPLE