Transcript Serial Offenders: Linking Cases by Modus Operandi and Signature Chapter 30

Chapter 30
Serial Offenders: Linking
Cases by Modus Operandi
and Signature
Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
1
Introduction to Crime Scene
Assessment
 Outcomes
possible from crime
scene assessment include:
 Determining
the physical, behavioral,
and demographic characteristics of the
unknown offender
 Developing post-offense behavior of
the offender and strategies for
apprehensions
Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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Introduction to Crime Scene
Assessment
 Developing
interviewing strategies
once the offender is apprehended
 Determining the signature of the
offender
 Determining where the evidence
may be located
Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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Introduction to Crime Scene
Assessment

Information used for analysis may come
from:
Police officer reports
 Statements
 Crime laboratory results
 Photographs
 Videotapes of crime scenes
 Autopsy reports

Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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Historical Perspective
MO- modus operandi or method of
operation
 Modus Operandi first appeared in
literature in 1654
 Chief Constable Major L.W. Atcherly of
England used ten categories related to
an offender’s modus operandi in 1879

Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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Atcherly’s 10 Categories
Classword
 Entry
 Means
 Object
 Time

Chapter 30
Style
 Tale
 Pals
 Transport
 Trademark

CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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Trademark
Atcherly’s trademark was the precursor
of what would have been known as the
signature today
 Trademark, according to Atcherly, was
whether the criminal committed any
unusual act in connection with the crimesuch as changing clothes, poisoning the
dog, leaving a note

Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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What is a Killer’s Signature
Also referred to as a killer’s
psychological calling card
 Homicide detectives are trained to look
for unusual characteristics: victim left in a
certain position, beaten or raped with a
certain instrument
 Subsequent killings of same type alert
detectives to possible serial qualities

Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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Differentiating MO and Signature

MO is simply the way a particular
criminal operates:

Using a glass cutter to break into building

Using a drill to open door locks

Way entry was gained
Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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Differentiating Modus operandi (MO)
and Signature

MO accounts for type of crime and
property attacked, including the person,
time and place of crime, tool or
implements used, way of entry, how
victim was caught, or how suspect
represented himself to victim
Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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Signature Versus Modus Operandi

FBI Behavioral Science Units and
representatives, such as John Douglas,
advise MO of killer is only those actions
necessary to commit the murder
Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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Signature Versus Modus Operandi

Signature is the killer’s compulsion to
express themselves

Imprint left at scene he feels
psychologically compelled to satisfy
himself sexually
Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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Signature Versus Modus Operandi
FBI defends the signature aspect of a
killer, saying that the elements of
personal expression will only develop
more fully over time
 According to Douglas, person’s violent
fantasies progress in nature over time,
and develops a need to develop those
fantasies

Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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Signature Versus Modus Operandi

According to Gerberth (1996), it is simply
not enough to consummate the murder,
the killer must act out fantasies in some
manner.

The acting out is the signature of the
killer
Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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Signature Versus Modus Operandi
Detectives who investigate a series of
murder scenes look for the same type of
extraordinary violence and a set of
bizarre similarities
 A signatures constitutes a strong
possibility the same person is committing
the crime

Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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Signature Versus Modus Operandi

Items a detective or investigator may
look for at a crime scene:
 How victim was placed, arrangement
of crime scene, preoccupation with a
certain aspect of the scene, mutilation,
overkill, body carving, engaging in
postmortem activity, making victim
respond in a certain manner
Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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Signature Analysis

Examples of clues to a serial killing in
the Shoreline Murders
Acts of binding occurring at consecutive
murders
 Number of stabbing strokes necessary for
killing
 Disposition of victim’s body- placement
 Taking of souvenirs
 Burning of bodies in certain areas

Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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Statistical Analysis
Homicide Investigation and tracking
System (HITS) in Washington State is a
central repository for murder and sexual
assault victims in state of Washington
 System has 227 query capabilities
 Other states and federal agencies have
similar systems

Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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Catching the Killer

Necessary items to catch a killer:
Thorough investigation of crime scene
 Cooperation with all agencies involved
 Review all evidence from witnesses
 DNA analysis and laboratory analysis of
evidence
 Coordinated efforts with prosecution

Chapter 30
CRC Press: Forensic Science, James
and Nordby, 2nd Edition
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