Transcript Introduction to Forensic Science

Introduction to
Forensic Science
SERIAL KILLERS
Serial Murders


Serial murders - repetitive homicides, nearly always
one-on-one murders, where the perpetrator is
usually a stranger or has a slight acquaintance to
the victim.
Historically, the majority of homicide victims knew
their killer, but during the 1990's, this figure changed.
Statistics from 1995's Uniform Crime Reports state
that 55% of homicide victims have no known
association with the perpetrators.

Berg & Horgan, Criminal Investigation, 3rd edition, pg. 332

Osterburg & Ward, Criminal Investigation, 3rd edition, pg. 455
Serial Murders

The serial murderer’s motivation to kill is not based on
crimes of passion, victim precipitation, personal gain or
profit.

Serial murderers are nearly always males prompted by
sexual or aggressive drives to exert power through
killing.
Modus Operandi
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
Modus operandi - a characteristic pattern of
behavior repeated in a series of offenses.
The following are categories of modus operandi
devised by Major L.W. Atcherley, an English
constable in the 1800's.
Classword - the kind of property attacked, such as a
house, a college dormitory, people parked in cars at
lover's lanes
 Entry - the point of entry, such as open bedroom
windows, sliding glass doors
 Means - implements or tools that were used, such as a
pry bar, ladder, screw driver

Modus Operandi

Object - kind of property taken, such as bras and panties

Time - time of day or night, weekdays, non-work days, holidays
(when people would not miss the perpetrator at work)

Style - the description the criminal gives the victim to gain entrance
(plumber, cable TV repairman)

Tale - any disclosure the criminal makes as to his business/purpose

Pals - any co-conspirators

Transport - what type of vehicle was used in connection with the
crime

Trademark - any unusual act committed by the suspect while in the
commission of the crime (i.e. poisoning the cat, eating at the scene
after murdering the grandmother)
Signature

Signature - the murderer's psychological calling
card, unusual characteristics of a murder that are
repeated at several crime scenes:

Intentionally displaying victims in a spread-eagle position.
This behavior reinforces the perpetrators underlying
psychological needs.
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Ted Bundy's choice of victims - young women with
blond or light brown hair, parted in the middle

John Wayne Gacy's victim type - adolescent boys
Green River Killer's victims - young women, mainly
prostitutes
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Difference Between Modus Operandi and
Signature
Two murderers both burn their victims by dousing them
with gasoline.
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
The first murderer
does so as an angerretaliatory act.
This is a signature
behavior.

The second murderer douses the
victim with gasoline to cover up
the crime.

This murderer does so to evade
detection.

This therefore is a precautionary
act, and as such is a modus
operandi behavior.
Characteristics of Serial
Killers
Usually intelligent
 Good appearance
Ted Bundy
 Superficial charm
 Able to differentiate right from wrong
 Have no conscience
 Enjoy victim's terror

Difficulties Faced by
Investigators
 Serial
murderers are often very mobile,
traveling from one locale to another to find
victims, extensive interstate travel
 Lack
 Use
of any prior association with the victims
of remote burial sites
Serial Killing
Versus Mass Murder

Charles Whitman, the man who shot multiple
people from the tower at the University of Texas,
was a mass murderer, not a serial killer

Dylan Klebold and Eric Harris, the shooters
responsible for killing 12 classmates and a teacher
in the deadliest school shooting in U.S. history, are
also classified as mass murderers, not serial killers
Organized Serial Killers
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Perpetrator plans the murder for months or years beforehand.
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Offender is normally married, has steady employment, and is
thought to be a good member of society (ex., BTK-Dennis
Rader)
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They bring the instruments of the crime (knives, guns, tape) to
the scene with them.
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When Ted Bundy was pulled over for driving suspiciously (in
1975), police found an ice pick, ski mask, rope and handcuffs in
his trunk.
These murderers are often highly intelligent and are
knowledgeable about forensic evidence and law
enforcement's investigative capabilities.
Disorganized Serial Killers
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They do not plan their crimes in advance.
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The disorganized murderer commits the crimes
spontaneously.

They are often unemployed and without
transportation.
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They are more often of low intelligence or
psychotic.
Psychological Types
of Serial Killers

Power Oriented – Ted Bundy and Dennis Rader enjoyed
watching terror of their victims
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Mission Oriented - killers feel they are improving the world
by getting rid of undesirable people such as prostitutes,
i.e. Green River Killer Gary Ridgway

Visionary - those who kill because they are directed by
hallucinations, i.e. David Berkowitz - "Son of Sam"
Psychological Types
of Serial Killers

Hedonistic - gain sexual satisfaction from raping, killing,
mutilating, and sometimes eating the victim, i.e. Jeffrey
Dahmer
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Comfort - those who kill for financial
gain, such as insurance benefits, real
estate, i.e. Golay & Rutterschmidt

Disciple - those killers who kill under the influence of a
charismatic killer, i.e. Leslie Van Houten and Lynette
Fromme of the Manson family
Psychological Profiles
of Serial Killers
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A psychological profile is a submitted report utilizing
information and approaches from various social
and behavioral sciences, focusing on a specific
type of violent crime
According to the FBI, a typical serial killer is a
Caucasian male between the ages of 18-32 who
has been a victim of child abuse and who has
exhibited signs of the McDonald triad
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McDonald triad – bedwetting after the age of 12, setting
fires, killing small animals
Psychological Profiles of
Serial Killers – McDonald Triad
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Most serial killers exhibit at least one of these behaviors
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According to Robert Ressler (FBI), more than 60% of serial killers
wet the bed past the age of twelve
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The Son of Sam, David Berkowitz, set 1,412 fires but switched
over to killing because it gave him more excitement and TV
news coverage
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Keith Jesperson, a serial killer from British Columbia who
murdered more than 160 victims, started with dozens of cats
and other small animals, before he moved on to human beings
Ted Bundy
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Intelligent, college educated, handsome man who
faked injuries and impersonated police officers to
gain access to
his victims.
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His criminal activity began as a peeping Ted and as
a shoplifter.
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While at the University of Washington, Bundy worked
for a suicide hotline with writer, Anne Rule, who later
wrote a bestseller “A Stranger Beside Me”.
Ted Bundy
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The majority of Bundy’s victims were young women with
blonde/light brown hair parted in the middle. Many
victims were stabbed, raped, tortured, and had been
strangled with panty hose. He desecrated and
dismembered them.
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Bundy confessed to killing 23 women between 1974-1978,
but the official toll may be closer to 100.
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Bite mark evidence from his victims at Florida State
University sealed his fate. Bundy was put to death in
Florida's electric chair in 1989.
Richard Ramirez
The Night Stalker
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Ramirez, avowed devil worshipper, randomly raped and
murdered his victims in their homes.
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Most of Ramirez's victims lived near freeways.
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In July 1989, Ramirez killed one of his victims, beat and
raped the man's wife, and then raped the couple's 8-yearold son.
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While in 8th grade, Ramirez began sniffing glue and
smoking marijuana. By the time he began killing, he had
graduated to shooting cocaine.
Lt. Gil Carrillo
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Lieutenant Gil Carrillo, of the LA Sheriff’s
Department, was the co-lead investigator of the
Night Stalker serial murder case.
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Ramirez’s AC/DC baseball cap, his size eleven and
a half Avia sneaker footprint, along with his
fingerprint found on a stolen car led to his capture
and conviction.