Crime Scene Investigation Case Studies Notes

Introduction: From the Scene of the Crime to the Desk of the Prosecutor

  • This chapter introduces methodologies of investigating and reporting criminal offenses beyond the initial response.
  • It includes a sample case for illustrative purposes.
  • Key Terms:
    • Case file
    • Chronological order
    • Complainant
    • Corpus delicti
    • Credibility
    • Elements
    • Fact investigation
    • Jargon
    • Linkage
    • Locard's Exchange Principle
    • Modus operandi
    • Narrative
    • Objective
    • Opinions
    • Reports
    • Solvability factors
    • Suspect
    • Victim

Learning Outcomes

  • Describe the differences between facts and opinions.
  • Explain the goals of an investigation.
  • Examine case narratives to determine investigative strategies.
  • Identify the elements of the crime under investigation.
  • Review case file documents for accuracy.
  • Recognize areas for improvement in case files.

Introduction

  • Investigative case files are the single tie that binds all phases of the criminal justice system together.
  • Poor police reporting can jeopardize effective criminal prosecution.
  • A wide spectrum of people will review the reports and case files, including supervisors, lawyers, prosecutors, judges, jurors, social workers, government officials, insurance adjustors and investigators, citizens, defendants, media representatives, crime lab analysts, and other investigating agencies.
  • This publication assists investigators and students in constructing solid, factual investigative case files.
  • These investigations are conducted daily in agencies of every size across the United States and throughout the world.
  • There is no “one size fits all” approach to acquiring the knowledge and skills required for successful case prosecution.
  • Investigation is successful when:
    • All gaps are filled between the statements.
    • Alternative explanations are considered but then eliminated.
    • A solid prosecutable case file is presented to the state’s attorney for review.
  • Not all investigations will result in arrests, prosecutions, or convictions.
  • The goal is to achieve justice by identifying and prosecuting guilty perpetrators, and exonerating the innocent.

Overview

  • In the United States, more than 16,000 law enforcement agencies generate reports daily.
  • Since 1838, when the Boston Police Department became the first official police agency in the United States, crime and offense reports have been written.
  • There is still no uniform or consistent method of collecting information when officers are called to provide assistance and begin an investigation.
  • Most law enforcement agencies have now moved to using standardized reports.
  • Regardless of technological advances, reporting requirements for law enforcement functions will always exist.
  • Proficient criminal investigators are difficult for police agencies to hire.
  • Developing and honing the skills to become an effective detective takes years of service and commitment. This is necessary to produce a high-quality, documented case file that accurately reflects every aspect of a case.
  • Depending on the circumstances, a few routine forms may need to be completed, and every action taken must be recorded.
  • If a crime has been committed, the appropriate response actions will be initiated.
  • Most actions taken by police officers and other first responders do not involve criminal activity.
  • The content must be complete, clear, concise, and accurate, whether the reports are typed or handwritten.

Investigative Case Files

  • The focus is on the investigative case file, which contains all documentation compiled by investigators who are examining every aspect of the event to determine the truth - what happened and who is responsible.
  • Questions addressed:
    • Was a crime committed?
    • What activities will be necessary to properly evaluate the circumstances and determine whether or not to proceed with a full investigation?
  • It is essential that all activities are documented so that any authorized individual reviewing the associated records will arrive at an informed decision regarding the investigation.

Terminology Used Throughout the Book

  • Report: Permanent records of all important facts in a case.
  • Fact: A statement that can be proven.
  • Accurate conveyance of information can create a linkage or association among a victim, the crime scene, and a perpetrator.
  • Investigation: A systematic and detailed inquiry to determine the truth and let the facts prove or disprove allegations. It also involves seeking to identify those responsible for the events and to eliminate the innocent from suspicion.
  • If a corpus delicti is established (evidence that a crime has been committed), a complete investigative file will present the best case possible for prosecution.
  • An investigator must establish elements of the crime, which are specific legal aspects of a criminal offense that must be proven. If a suspect is charged with the offense, all elements must be established beyond a reasonable doubt.
  • Determining the truth is more important than obtaining a conviction or closing a case.
  • Good investigators establish credibility by remaining unbiased and impartial, and those traits will be reflected in their written work. Credibility is hard to establish and easy to lose.
  • Solvability factors: Statements that are crucial to solving crimes and in prioritizing caseloads. The data are used for compiling statistics, and the victim (if insured) will provide a copy of the report for claim reimbursement; then the case is removed from active investigation.
  • Narrative: A well-structured narrative focuses on content and factual statements. There is never any room for opinion in this type of report.
    • Use the first-person, past tense, active voice, and present the events in chronological order.
    • Use short, clear, concise, and concrete words to explain the situation.
    • Avoid jargon, which consists of words, expressions, or phrases specific to a profession or occupation.
  • Take detailed notes on every step taken in every investigation.
  • Your opinion has no place in the reports. Opinions are beliefs that may not be accurate and may not be provable, whereas facts are tangible things used to make solid decisions and that can be proven.
  • Objective documents and statements display no bias, are non-opinionated, fair, and impartial.
  • Establish a timeline, or sequence of the events, following chronological order.
  • Establish the corpus delicti, or “the body of the crime.” This does not literally mean that a body must be discovered, but it must be proven that someone has committed an offense.

The Purpose of This Book

  • Each chapter involves a different type of criminal offense.
  • Assume the role of investigator, read the case narrative, and then identify the steps you will take to conduct the investigation (your investigative strategy) and the accompanying documentation that must be completed.
  • Identify the criminal offenses that have occurred and their elements.
  • Create a timeline as you review the narrative.

Primary Goals of an Investigation

  • Discover the truth by determining whether or not a crime was committed.
  • Identifying those responsible.
  • Eliminating the innocent from suspicion.
  • Legally obtaining information.
  • Compiling the best possible information for prosecutorial purposes.
  • An investigator must be able to interview and write reports and must be thoroughly familiar with crimes and their elements.

Important Information for Every Investigation

  • No two cases are alike.
  • Even if you identify a serial offender who continually commits the same offense, the circumstances always vary.
  • Modus operandi: A method of operation
  • Victims can be individuals, groups of people, or corporations.
  • Complainant: The person who reports an incident to the law enforcement agency responsible for responding to that specific jurisdiction. The complainant may or may not be a victim of a crime.
  • Actions that are in violation of local ordinances, state statutes, and federal laws are criminal acts.
  • The elements of a criminal offense are clearly identified in the state statutes.
  • Prosecutors will check your work to ensure you have established the corpus delicti.

Descriptor Information for Every Suspect

  • Collect as much data as possible.
  • Proof that a crime has occurred must be established as the first step.
  • Your investigation should identify a person or persons who appear to be directly or indirectly connected with the crime.
  • Not everyone you encounter in the investigation will be a suspect, so remain unbiased and nonjudgmental.

Review of Basic Crime Scene Investigation

  • Locard’s Exchange Principle: Every contact leaves a trace. When a perpetrator enters a crime scene or interacts with a victim, the perpetrator leaves something at the scene and takes something away—that is, there is an exchange of physical evidence.
  • Investigators must work closely with crime scene investigators (CSIs) as they process the crime scene or the victim.

Elements of a Case File

  • Incident or offense report

  • Supplemental report(s)

  • Victim or witness statement(s)

  • Entry/exit log

  • Photo log

  • Crime scene rough sketch

  • Crime scene final sketch

  • Evidence/property sheet

  • Chain of custody log

  • Investigative strategy

  • Timeline

  • Miranda rights waiver

  • Field interview card

  • Affidavit for search warrant

  • Search warrant

  • Affidavit for arrest warrant

  • Arrest warrant

  • Suspect statement

  • Consent to search waiver

  • Request for crime laboratory examination

  • Crime laboratory analysis report

  • Polygraph examination report

  • Autopsy report

  • Arson investigation report

  • Photo lineup form

  • Vehicle inventory/tow sheet

  • Arrest report

  • Booking sheet

  • The cases you are reviewing were developed by a group of graduate students studying criminal justice at Charleston Southern University.

  • Documentation, including photographs, crime scene sketches, statements, search warrants, lineups, and so on, were identified as necessary in order to build a case file that could be presented to the prosecutor’s office to press charges on behalf of the state.

Sample Case: Critical Questions and Activities

  • Review the case narrative and construct a timeline.

  • Familiarize yourself with the forms and reports contained within the case file.

  • List the elements of each of the crimes contained in the case file.

  • Create a list of additional physical evidence you believe should have been collected and what type of scientific testing you would request from the crime lab.

  • Explain the key investigative strategies and describe how you as the case investigator would address those problem areas in this case file.

  • CSI Officer Roberts responded to a street address adjacent to a location where firefighters were extinguishing a house fire.

  • The reporting officer, Lonnie Downs, had spotted a pool of blood in the street in front of the residence. The residence was on fire, but no victims had been located.

  • The amount of blood indicated a severe loss of blood victim should be found.

  • Officer Downs canvassed the neighborhood, and CSI Officer Roberts took photographs and created a crime scene diagram.

  • Officer Downs used string to map out the path of the blood droplets to determine where the indicators converge and identify whether the victim was standing or sitting as the blood droplets were falling. The measurements indicated that the point of impact was the front bumper of the fire engine.

  • Officer Downs questioned the fire truck engineer, who stated he had not seen anyone around the area when they arrived on the scene.

  • Both a fire supervisor and a police supervisor were summoned to the scene.

  • When the lead fire truck was pulled back to depart, a body was discovered underneath the truck.

  • The victim was struck by the lead fire truck and had crawled back under the vehicle where he later expired.

  • CSI Roberts had photographs, a sketch, and a stringing diagram of the crime scene. Officer Downs had already begun to complete the preliminary investigation report and had identified all the first responders on the scene.

  • The victim was an opossum.

  • Not all investigations lead to criminal prosecutions.

  • Police officers encounter unexpected outcomes throughout their careers.

  • There is no room for second-guessing or taking shortcuts when conducting an investigation and building a case file.

  • Sometimes you will discover no crime was committed; however, every investigation demands that protocols and standard operational procedures be completed.

And Finally

  • The key to success is to allow the evidence to speak for itself.
  • An investigator does a thorough and ethical investigation and then hands that case file over to the prosecutorial branch of the American criminal justice system.
  • Criminalist Paul Kirk penned these words back in 1953:
    • Locard's Exchange Principle restated: However careful a criminal may be to avoid being seen or heard, he will inevitably defeat his purpose unless he can also control his every act and movement so as to prevent mutual contamination with his environment, which may serve to identify him.… Wherever he steps, whatever he touches, whatever he leaves—even unconsciously—will serve as silent evidence against him. Not only his fingerprints and his shoeprints, but also his hair, the fibers from this clothes, the glass he breaks, the tool mark he leaves, the paint he scratches, the blood or semen that he deposits or collects—all these and more bear mute witness against him.… Physical evidence cannot be wrong; it cannot perjure itself; it cannot be wholly absent. Only in its interpretation can there be error. Only human failure to find, study, and understand it can diminish its value.

Discussion Questions

  • List four people outside the law enforcement agency who may review police reports.
  • What are three differences between facts and opinions? Why do you need to be able to provide this explanation?
  • Where are the elements of each specific crime identified? Why is it important to document the elements of a crime in the case file?
  • Why is it necessary to develop a timeline for every investigation?
  • Criminalist Paul Kirk tells us that physical evidence cannot be wrong, but the interpretation of that evidence can leave room for error. Why is that statement important to criminal investigators?