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Swanson, Criminal Investigation 8/e
Criminal Investigation, 8/e
Charles R. Swanson, University of Georgia
Neil C. Chamelin, Assistant State Attorney, Second Judicial Circuit
Leonard Territo, University of South Florida- Tampa

Investigators, the Investigative Process, and the Crime Scene

Chapter Outline

I. TYPES OF OFFENSES (See Slides 2-1 and 2-2)

A. A crime is the commission (the "doing") or omission (failing to do) of any act which is prohibited or required by the penal code of an organized political state.

B. In most states a felony is an act punishable by imprisonment for a term of one or more years or by death.

C. Generally, violations of the criminal code which are not felonies are designated as misdemeanors, lesser offenses which may be punishable by a fine not to exceed $500 and/or imprisonment for not more than one year.

D. Some states have a third crime category called a violation, e.g., criminal littering, which are punishable only be a fine of not more than $250.


A. An investigator is someone who gathers, documents, and evaluates evidence. The investigative process had the following objectives: (See Slides 2-4 and 2-5)

1. To establish that a crime was actually committed.

2. To identify and apprehend the suspects(s).

3. To recover stolen property.

4. To assist in the prosecution of the person(s) charged with the crime.

B. Essential Qualities of the Investigator

1. The investigator is someone with strong professional training and solid experience who by carefully completing every appropriate step in an investigation leaves nothing to chance.

2. Investigators must use both inductive and deduction reasoning. (See Slides 2-6, 2-7 and 2-8)


The major events in the investigation of crime follows.

A. The Preliminary Investigation (see Slide 2-9)

The actions taken at the scene of a crime immediately following its detection and reporting constitute what is termed the preliminary investigation (See Slide 2-10).

1. Receipt of Information and Initial Response

2. Emergency Care

3. Crime Scene Control

4. Issue A Be On The Lookout Alert for Suspects

5. Crime Scene Determination

6. Evidence

7. The Incident/Offense Report

B. The Follow-up Investigation

Follow-up investigation is the effort expended by the police in gathering information subsequent to the initiation of the original report until the case is ready for prosecution or closed. (See Slide 2-11)


Crime scenes vary with the amount of physical evidence which is ordinarily expected to be recovered; a murder scene in a motel room will yield more physical evidence than a yard from which a lawnmower was stolen. At the most basic level, a "crime scene" is the location where the offense was committed. (See Slides 2-12 and 2-13)

A. There are several ways to think about what a crime scene is.

1. Criminal incident may have more than one crime scene.

2. Based on size, there are macroscopic and microscopic scenes.

3. Other useful ways of thinking about crime scenes are based on the type of crime (larceny versus aggravated assault), the location (indoors or outdoors), the condition of the scene (organized or disorganized), and the type of criminal action (active or passive).


The work at the crime scene is divided into three functions: 1) overall coordination of the scene; 2) technical services, and 3) investigative services. (See Slides 2-16 and 2-17)

A. Overall Coordination

Ordinarily, this first function is vested in the senior investigator at the scene and she or he will have the final responsibility for what is done at the scene and what types of additional resources will be requested.

B. Technical Services

This function is the responsibility of the ranking representative of the department’s central crime laboratory or its crime scene processing unit, along with any subordinate specialists who are assigned to the scene.

C. Investigative Services

Investigative services include interviewing witnesses, conducting and documenting the neighborhood canvass discussed earlier, a field interrogation of the suspect, if in custody, and carrying out and recording the results of a vehicle information canvass.

D. Categories of Evidence

There are three broad categories of evidence in which investigators have a particular interest: 1) corpus delicti, 2) associative, and 3) tracing. (See Slide 2-10)

VI. TYPICAL CRIME SCENE PROBLEMS (see Slides 2-18 and 2-19)

Although the procedures to be followed at a crime scene investigation may be neatly delineated in theory, any number of conditions may render their accomplishment a good bit less orderly than the ideal.


A. One: Maintenance of Control

Without control a life might be lost, evidence destroyed, assignments overlooked, or the investigation conducted in a generally slovenly manner. (See Slides 2-18 and 2-19)

B. Two: Conceptualization

In processing the crime scene, it is necessary to keep both known facts and inferences in mind. This facilitates the reconstruction of the offense and identification of the perpetrator’s method of operation, suggests the possible existence of certain types of physical evidence, and assists in establishing appropriate lines of inquiry.

C. Three: Caution

In approaching the point of focus, minute but extremely important evidence may be altered or destroyed; the area to be searched may be too rapidly defined; and other areas that might be fruitfully explored are overlooked or given only a cursory examination.

D. Four: Inclusiveness

The rule of inclusiveness dictates that every available piece of evidence be obtained and where there is a question as to whether a particular item constitutes evidence, be defined as such.

E. Five: Documentation

Document of the crime scene is a constant activity, starting with the rough, shorthand record created by field notes. In lesser offenses, a single officer may be the only representative of the police department at the scene. Thus, everything which is learned will be a result of his or her investigation. In such cases the only documentation which may exist is the officer’s field notes and the Incident/Offense report. (See Slides 2-20 and 2-21)


There are numerous threats to investigators health and safety.

A. Infectious Diseases


The HIV virus is a blood-borne pathogen which is also present in other bodily fluids.

2. HIV/AIDS and Investigators

At crimes, accidents, and other scenes with a potential or known HIV risk investigators should have certain knowledge and employ self-protection techniques.

3. Hepatitis B and C

Hepatitis B (HBV) is the most common serious disease in the world and it is the leading cause of liver cancer.

4. Tuberculosis

Tuberculosis (TB) is a chronic bacterial infection which is the leading infectious disease killer in the world; it is spread by the air and usually infects the lungs, although other organs may be involved.

B. The Americans with Disability Act (ADA)

Investigators who contract such infectious diseases may be covered by federal Americans with Disability Act (ADA), which makes it illegal to discriminate against otherwise qualified employees in employment actions—such as assignments and promotions—solely on the basis that an investigator is thought to have or actually has a covered disability.


The purpose of the crime scene search is to obtain physical evidence useful in establishing that, in fact, an offense has been committed; identify the method of operation employed by the perpetrator; reduce the number of suspect; and identify the perpetrator.

A. The Five Major Considerations (see Slide 2-24)

1. One: Boundary Determination

In terms of the boundary of the crime scene, it is useful to think of an inner perimeter and an outer perimeter.

2. Two: Choice of Search Patterns

There are five fundamental search patterns from which the crime scene coordinator may select. (See Slide 2-5)

3. Three: Instruction of Personnel

Even when the same type of criminal offense has been committed, the variation among crime scenes may be enormous. Thus, it is of paramount importance that the crime scene coordinator call together all those individuals who will be, in various capacities, processing the scene and share with them all of the available information concerning the case.

4. Four: Coordination

One of the most important responsibilities of the person in charge of the crime scene is to integrate the efforts of those assigned to the technical and investigative service functions, along with ensuring the timely flow of pertinent information.

5. Five: Documentation

It is important to thoroughly document all aspects of the crime scene search.


A. The amount of time required to process a crime scene varies considerably.

1. The search should only be terminated after all avenues for developing physical evidence have been explored.

2. A thorough debriefing involving all members of the crime scene search should take place before the release of the crime scene.


The location of physical evidence during the crime scene search merely marks the first step in its long journey toward presentation in court.


Occasionally, the value of an otherwise excellent investigation is reduced by improperly or inadequately documenting the scene visually. (See Slides 2-26 and 2-27)

A. Video Taping

Using a video camera to document the crime scene offers several advantages. Such cameras are relatively inexpensive, they incorporate audio, their use can be quickly learned, the motion of videotapes holds the attention of viewers, and the images collected can be played back immediately.

B. Photographing

1. General Guidelines

In addition to videotaping, major crime scenes should be documented using other cameras and techniques.

C. Sketching

1. Sketching Methods

It is critical that measurement shown on the sketch be as accurate as possible and that they be made and recorded uniformly; if one aspect is inaccurate, such as the dimensions of a field in which a body was found, the distortion introduced renders the sketch relatively useless.


Evidence submitted to a crime laboratory is most often transmitted by courier, air express, or registered mail. In general the method of transmitting evidence is determined by the nature of the evidence and the urgency of getting an analyst’s conclusions. Federal and state agency rules specify how some special classes of evidence must be sent.