chapter 30 crc press: forensic science, james and nordby, 2nd edition1 chapter 30 serial offenders:...

Chapter 30 CRC Press: Forensic Science, James and Nordby, 2nd Edition

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Chapter 30

Serial Offenders: Linking Cases by Modus Operandi

and Signature


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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


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Developing interviewing strategies once the offender is apprehended

Determining the signature of the offender

Determining where the evidence may be located


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Information used for analysis may come from:Police officer reportsStatementsCrime laboratory resultsPhotographsVideotapes of crime scenesAutopsy reports


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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


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Atcherly’s 10 Categories

ClasswordEntryMeansObjectTime

StyleTalePalsTransportTrademark


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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 crime- such as changing clothes, poisoning the dog, leaving a note


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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


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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


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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


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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


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Signature is the killer’s compulsion to express themselves

Imprint left at scene he feels psychologically compelled to satisfy himself sexually


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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


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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


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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


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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



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Signature Analysis

Examples of clues to a serial killing in the Shoreline MurdersActs of binding occurring at consecutive

murdersNumber of stabbing strokes necessary for

killingDisposition of victim’s body- placementTaking of souvenirsBurning of bodies in certain areas


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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 capabilitiesOther states and federal agencies have

similar systems


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Catching the Killer

Necessary items to catch a killer:Thorough investigation of crime sceneCooperation with all agencies involvedReview all evidence from witnessesDNA analysis and laboratory analysis of

evidenceCoordinated efforts with prosecution

chapter 30 crc press: forensic science, james and nordby, 2nd edition1 chapter 30 serial offenders:...

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