Chapter 7

Chapter 7
Specialized Roles of Police
Police may be required to perform
specialized functions.
Large Departments may have specialized
officers to deal with specific problems
Suppressible Crimes: Crimes that
commonly occur in locations and under
circumstances that give police officers a
reasonable opportunity to deter or
apprehend offenders
Specialized operations are often used to saturate
particular areas or to stake out suspects and
possible crime locations.
CSI effect
Forensic Science deals with examining physical
evidence to answer legal questions. Forensic
experts can be found in a wide array of
occupations, including forensic accounts,
anthropologists, artists, chemists, dentists,
geologists, pathologists, psycholinguists,
psychologists and toxicologists
Criminalistics is a branch of forensic science that
deals with physical evidence related to a crime.
This may include fingerprints, firearms, tool
marks, blood, hairs, documents and other types
of physical evidence.
The primary characteristic of an effective
investigator is objectivity.
The investigator seeks the truth, not simply
proof of the suspects guilt.
Preliminary Investigation consists of action
performed immediately upon receiving a call to
respond to the scene of a crime scene of a crime
and is usually conducted by patrol officers
Follow-up Investigation: may be conducted by
the investigative services division, sometimes
also known as the detective bureau. Successful
investigation relies on cooperative, coordinated
efforts of both the patrol and the investigative
Investigative Responsibilities:
Securing the crime scene
Recording all facts related the case
Photographing, measuring and sketching the
crime scene
Obtaining and identifying evidence
Protecting and storing evidence
Interviewing witnesses and interrogating
Assisting in identifying suspects
Any area that contains evidence of criminal
activity is considered a crime scene and must be
secured to eliminate contamination.
Contamination means to introduce something
foreign into the scene, moving items at the
scene or removing evidence from it.
Investigators record all necessary information by
photographing, sketching, taking notes to be
used later in a written report
The investigator must obtain answers to
questions: who? What? When? Where?
How? And Why?
Investigators do NOT DETERMINE GUILT!
Both photographs and sketches are
usually needed in an investigation. The
photographs include all details and can
show items close up. Sketches can be
selective and can show much larger areas.
Some agencies have established evidence
The type of evidence collected is directly
related to the type of crime committed.
Scenes of violent crimes frequently
contain such evidence as blood, hair,
fibers, fingerprints, footprints and
DNA: the basic building block comprising each
person’s genetic code. DNA is found in virtually
every cell in a person’s body, including blood,
semen, hair and skin cells, and it provides a
blueprint for the various characteristics that
make each person unique.
DNA Profiling uses the material from which
chromosomes are made to positively identify
individuals. No two individuals, except identical
twins, have the same DNA structure.
CODIS: The FBI’s Combined DNA Index System
is an electronic national database and searching
mechanism containing hundreds of thousands of
DNA profiles obtained from evidence samples
from unsolved crimes and from know offenders.
Firearms as evidence may be traced to its owner
through the serial number. The make of the
weapon is usually determined by the rifling,
spiral grooves cut into a gun’s barrel during it
Ballistics deals with the “internal (within the
weapon), external (after the projectile leaves the
muzzle and before impact), terminal (after the
bullet impacts and comes to rest) and forensic
(examining comparisons of projectiles/cases and
their relationship to firearms)
Interviewing and Interrogating:
A large part of any investigation is talking with
people to obtain information.
Investigators interview those with information
about a crime.
A witness is a person other than the suspect
who has helpful information about a specific
incident or suspect. A witness may be a
complainant (the person reporting the offense),
an accuser, a victim, an observer of the incident,
an eyewitness, an expert or a scientific examiner
of physical evidence.
Officers may also use informants, an
individual who did not witness the offense
but knows something about who
committed it. While informants may
receive money as a reward, most
informants cooperate with law
enforcement to receive a reduced
sentence for pending criminal matter.
While investigators talk to suspects, they
technically interrogate suspects, although the
questioning may be called an interview. Many
departments videotape interviews and
interrogations to protect against liability.
Three basic types of identification are:
Field identification
Photographic identification
Lineup identification
Field identification: is at the scene identification,
made within a short time after a crime has been
Field identification is based on a totality of
circumstances, taking into consideration the
witness’s concentration on the suspect when the
crime was committed, the accuracy of the
description, the certainty at the time of the
confrontation and the length of time between
crime commission and the field identifcation.
Another way to identify a suspect may be the
Modus Operandi or M.O.
Relatively superficial characteristics to identify
suspects, such as height, weight, race, gender,
age, accent, type of car drive, M.O. and so on.
Intelligence Officers:
Most large departments have an intelligence
division whose top officer reports directly to the
chief and whose activities are keep from the rest
of the department.
Intelligence units work in two areas:
Undercover or internal affairs
Undercover work involves ongoing investigations
into such criminal activities as illegal sale of
guns, payoffs to politicians, major drug cases
and organized crime.
Undercover officers do not wear uniforms or
drive marked cars. They may assume names and
fictitious identities.
Light Cover and Deep Cover
Light cover officers usually have fake id’s
but go home to their families and real like,
most likely in another city.
Deep Cover live their roles 24/7, with a
false ID and a false personal history.
Internal Affairs:
Policing the Police
Respond to citizens complaints and
misconduct by police.
Juvenile Officers: A special kind of
“juvenile officer” is the School Resource
Officer. These programs offer an
opportunity for school officials to
proactively protect their school and
improve their education
SWAT Team officers are immediately
available, flexible, mobile officers used to
deploy against critical incidents. They seek
to contain and neutralize dangerous
SWAT (Special Weapons and Tactics)
began in 1967 when the Los Angeles
Police Department organized such a unit
to respond to critical incidents.
K-9 Assisted Officers:
The first organized K-9 unit in the US
began in 1907 in New York City.
K-9’s are used to detect concealed
suspects, drugs, weapons and explosives,
fund evidence discarded by fleeing
suspects; control crowds and break up
fights, recover lost articles; and locate
distressed person and dead bodies.
K-9’s may be specifically trained in search,
attack and capture, drug detection, bomb
detection and crime deterrence.
Various breeds of dogs are used, but the
most popular is the German Shepherd.
K-9 Case Law:
Most issues revolve around the 4th
amendment-unreasonable search and
In US v. Place (1993) the US Supreme Court
ruled that the exposure of luggage to a canine
sniff did not constitute a search.
The courts have usually sided with law
enforcement on the use-of-force issue.
Devanney and Devanney (2003) report: “Several
courts have already held that properly trained
police dogs does not constitute deadly force.”
Dogs are often considered reasonable force, not
deadly force.
Reserve Officers: Some Departments have
reserve units to help achieve departmental
Can be called auxiliary police.
Beside performing traditional street patrol,
reserves may be found on bicycles, in the
water and in the air.

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