Douglas, retired FBI behavioral scientist wrote the first psychological
profile of the Green River killer in 1982.
Serial killers driven
to act out the same type of brutality repeatedly, leave psychological
markers. "In multiple-victim cases, we always look to see
if there is a signature so we can tie victims together,"
said King County sheriff's Sgt. John Urquhart.
Elements of the signature
could be gratification after death, posing or concealing the victims
and inserting objects into their bodies. A
killer's signature intensifies as the killer learns through experience
what types of violence and reactions arouse him. The need to punish
and degrade the victim is constant.
Douglas and Robert
Keppel, former detective, criminologist and consultant to the
Green River Task Force, believe sadistic sexual killers cannot
stop themselves. Keppel believes the Green River killer continued
likelihood of stopping is real small," Keppel said. "Every serial
killer we know of in history has continued until he is stopped."
"I don't think
he changed the target population, but I think he changed things
enough so we weren't smart enough to see it," said Bob Gebo,
former task force member, now on the Homicide Information Tips
Systems team. Gebo feels there were killings after 1984.
Emanuel Tanay, forensic
psychiatrist, speculates the Green River killer might have stopped
killing because he married and developed a sadomasochistic relationship
that fulfilled his needs, at home. "He was torturing that person
emotionally or physically, and it gratified his need."
is not a hard science like DNA analysis. Experts don't always
To tie 45 unsolved
killings investigators may need to rely on a signature. Keppel
Green River killer has an unusual
signature in the slayings that occurred both before and after
the time span of 1982 to 1984.
as an Investigative and Prosecutorial Tool
The King County Prosecuting
Attorney's Office successfully used signature analysis to get
convictions. In the 1991 trial of George Russell.
Keppel said, "If
your case is not as strong on one murder, you could testify about
behavioral characteristics and how they are maintained throughout
all the murders. So, whoever did Number 1, they also did Number
2 and Number 3."
Keppel won't say what
that signature is in the Green River case, revealing it could
interfere with trial proceedings. Detectives and prosecutors will
not discuss possible trial evidence.
- Mode of Operation - MO
A common mistake is
to confuse a signature with a modus operandi, mode of operation
This is the series
of actions required to find, subdue and kill a victim, and escape
detection. "MO is dynamic and changes as the killer finds
out what works better,"Keppel
MO includes the type
of victim taken (prostitutes and hitchhikers), where they were
last seen ( Sea-Tac strip), and the way the bodies were found
in clusters (5 and 6 bodies found buried in close proximity of
each other). Clusters are strong evidence that only one person
(or perhaps 2 acting together) was responsible for the murders.
A killer's signature,
consists of actions above and beyond the MO.
A killer may arrange,
pose or degrade the body, after death, for their own gratification
and fantasies. Posing is rare found in less than 1% of murder
cases, according to Keppel. Insertion of objects in a victim's
body after death is found in fewer than 1 in 1,000 slayings.
Ann Christensen, was found fully clothed, with two fish placed
on her chest, a wine bottle on her stomach, and sausages in her
Douglas wrote posing
indicated the killer knew his victim. Before his arrest, Ridgway
told detectives he knew Christensen,
but did not have sex with her.
"By the time he got
to Christensen, he was no rookie," Keppel said.
Two Green River killer
victims, Chapman and Hinds,
were found with small triangular stones inserted in their vaginas.
is different than MO or signature, staging is moving a body to
mislead those attempting to locate it.
The remains of 37 victims
were found in remote areas. Some victims' bodies have never been
found (at least 7).