Learning Objectives

After reading this chapter, students should:

1. List the three primary purposes of police patrol.

2. Indicate some investigation strategies that are considered aggressive.

3. Describe how forensic experts use DNA fingerprinting to solve crimes.

4. Explain why differential response strategies enable police departments to respond more efficiently to 911 calls.

5. Explain why reactive arrest strategies might be incompatible with problem-oriented policing.

6. Determine when police officers are justified in using deadly force.

7. Explain why police officers are allowed discretionary powers.

8. Explain what an ethical dilemma is, and name four categories of ethical dilemmas that a police officer typically may face.

Lesson Plan

Correlated to PowerPoints

I. Police Organization and Field Operations

Learning Objective 1: List the three primary purposes of police patrol.

Learning Objective 2: Indicate some investigation strategies that are considered aggressive.

Learning Objective 3: Describe how forensic experts use DNA fingerprinting to solve crimes.

A. image1.emf







The model of the modern police department is bureaucratic, with formal rules governing the actions of each member of the agency


B. The ultimate goal of the bureaucratic model is to reach maximum efficiency

C. The Structure of the Police Department

i. Each police department is organized according to its environment: the size of its jurisdiction, the type of crimes it must deal with, and the demographics of the population it must police

ii. Chain of Command

a. Regardless of size and structure, every department needs a clear rank structure and strict accountability to ensure proper functioning

b. Begins with the rank of chief down through the various levels

c. Delegation of authority

1. A critical component of the chain of command

2. Nearly every member is directly accountable to a superior officer

3. Connection encourages discipline and control while lessening unsupervised abuses of freedom

iii. Organizing by Area and Time

a. In metropolitan areas, police responsibilities are divided according to zones called beats and collection of beats called precincts, districts or a station

b. Most departments separate twenty-four hour day into three eight-hour shifts, also called tours or platoons

iv. Law Enforcement in the Field

a. The main goal of the department is the management of its field services, or operations or line services which include patrol, investigations, and special operations

b. Most police departments are generalists; police officers are assigned to general areas and perform all field services within boundaries of their beats. Large departments may be more specialized

D. Police on Patrol: The Backbone of the Department

Patrol officers are considered to be on the lowest rung of hierarchy, yet compose as many as two-thirds of a department’s sworn officers, and are considered the most valuable members of the agency.

i. The Purpose of Patrol

a. Deterrence of crime through maintenance of visible police presence

b. Maintenance of public order and a sense of security in the community

c. Twenty-four hour provision of services that are not crime related

ii. Patrol Activities

a. Preventative patrol through maintenance of police presence within the community, which takes 40% of patrol time

b. Responding to calls for service during 25% of patrol time

c. Administrative service, including paperwork, which comprises almost 20% of patrol time

d. Officer-initiated activities, such as contacts with citizens and speaking with pedestrians takes the remaining 15% of patrol time

E. Police Investigations

i. Considered to be the second main function of policing, through reactive means

ii. Delegated to the investigator, or detective

a. Most commonly promoted from patrol

b. Must prepare cases for trial

F. Aggressive Investigation Strategies

i. Undercover Operations

a. Detective bureaus can implement more aggressive strategies

b. Going undercover is considered a dangerous and controversial activity

c. Confidential informants may provide access to information about criminal activities

ii. Preventive Policing and Domestic Terrorism

a. Confidential informants can help prevent terrorist acts

b. Issue of entrapment

G. Clearance Rates and Cold Cases

a. The ultimate goal of all law enforcement is to clear a crime

b. Clearance rates vary based on the type of offense

c. Clearance rates also reflect the resources the agency expends on the particular type of crime

d. The clearance rate for violent crimes has been dropping for decades

e. As a result of low clearance rates, police departments are saddled with a growing number of cold cases, or criminal cases that have not been cleared after a certain amount of time

H. Forensic Investigations and DNA

i. Forensics is the practice of using science and technology to investigate crimes

ii. Forensics can be used to determine key elements of a crime, such as

a. The cause of death or injury

b. The time of death or injury

c. Type of weapon or weapons used

d. The identity of the crime victim

e. The identity of the offender

iii. Many police departments operate or are affiliated with crime laboratories

iv. Crime Scene Forensics

a. The first officer on the scene has the important task of protecting trace evidence, or very small pieces of evidence, from contamination

1. Trace evidence includes blood, fibers, fingerprints, hairs, etc.

b. Police will search a crime scene for bullets and spent cartridge casings.

1. The study of firearms, including the firing of the weapon and the flight of the bullet, is known as ballistics

c. Has been the most important piece of trace evidence for centuries

d. This method of identification is not infallible

1. It is often difficult to lift a suitable fingerprint from a crime scene.

v. The DNA Revolution

a. DNA is the genetic code for every living organism

b. DNA has supplanted fingerprinting as the most important piece of forensic evidence

c. No two people, except for identical twins, have the same DNA

d. A match can exclude a suspect, or identify one conclusively at the odds of 30 billion to 1.

vi. DNA in Action

a. The ability to gather DNA from a wide variety of evidence greatly increases the odds a crime will be solved

b. Databases and Cold Hits

1. National Combined DNA Index System (CODIS) stores the DNA profiles of offenders who have been convicted of murder and sexual assault

2. Cold hits occur when DNA samples from the crime scene match a profile included in the CODIS database

c. New Developments

1. The investigative uses of DNA fingerprinting are expanding rapidly

2. Taking advantage of a new technique known as “touch DNA,” investigators can collect evidence from surfaces that are not marked by obvious clues such as bloodstains or well-preserved fingerprints.

3. DNA sample taken from a crime scene soon may be able to provide law enforcement with a physical description of a suspect, including her or his eye, skin, and hair color and age.

Media Tool

“Latest Victory for the California Innocence Project”


· A short clip about the exoneration of Brian Bank

Place Your Order Here!

Leave a Comment

Your email address will not be published. Required fields are marked *