Abstract
A
Polygraph, often referred to as lie detector test, is a device which records
the several physiological changes in one’s body such as heart rate, blood
pressure, respiration, skin conductivity while a person is asked and answers a
series of questions. The principle underlying the use of polygraph test is that
deceptive answers and non deceptive answers will produce different
psychological responses but there are no specific psychological responses or reactions
which can be associated with lying which makes it difficult to identify factors
that separate those who are lying and those who are telling the truth. In many
countries, this polygraph test is used by investigating officer, Police, FBI
etc. as an interrogation tool for the suspect. Polygraph testing is used in
high profile cases and only when there is no alternative way to find out the
truth and continue the investigation. However, reliability of polygraph testing
is not higher as it does not give the 100 percent correct answers, smart
suspects or criminals can overcome this test also with confidence and
controlling their own biological response to the questions like blood pressure
and heart rate, but it helps to reduce the number of possible suspects.
Key
words: Polygraph testing, physiological
response, Lie detector test, High profile cases, Reliability.
Introduction
Susan
Smith had been separated from her husband David Smith and had been seeing Tom
Findlay who was a successful businessman and had recently broke off their short
relationship with Susan with the reason that he is not comfortable about
getting involved with someone who had already two children. And with this breakup
Susan started threatening with suicide notes.
Case
Study report
On
the evening of October 24, 1994 Susan smith pounded on the front door of a
house in town of south Carolina and when the unknown owner of the house opened
the door found Susan crying profusely and screaming that her children had been
kidnapped. When police arrived, Susan told them that a middle-aged black man
with gun had forced her out of the car while she was waiting with her two
children Alex, 1 year old and Michael, 3 year old at the red light. She further
stated that kidnapping has occurred near John D long Lake.
Police
started investigation but they did not find anything from the long
investigation and soon become suspicious of Susan because of inconsistencies in
her story after numeral questioning periods. Sketch artist stated that the
description of kidnapper by Susan was first vague and later become more
detailed whereas a truthful person first give detailed appearance and then
description becomes vague.
Three
days after the incident polygraph test was conducted on David and Susan which
indicated that David has no involvement in this incident. But Susan test
results were inconclusive. Suspicion of police increase more when after
questioning her, she told that her car was the only one stopped at the
intersection and street light colour changes only when there are more than one
car. And, she again changed her statement saying that abduction took place in
Monarch Mill intersection two miles from the original location.
Police
began a new approach with Susan by bringing Pete Logan who was an FBI agent
with 30 years of experience and a trained polygraphist. He gently gained the
trust of Susan and continued polygraph test but she was not likely to tell the
truth. On November 3, 1995 nine days after the disappearance of children, Susan
met Agent Logan that afternoon, and after repeated questioning she again
changed the location saying it took place in Carlisle intersection. Agent Logan
had to leave Susan by saying that he had to attend a phone call which was a
plan for interrogation plan and then Sheriff Tom Wells, initial investigating
officer went to talk to Susan and had known her many years. He told her that
the kidnapping could not have happened at Carlisle intersection as at the night
of kidnapping there were many undercovers officers at intersection on a mission
of drug settlement which was lie, it was only a trap by officers for Susan.
Sheriff told Susan ‘It is the time’ and then she admitted that she was
depressed, lonely and wanted to kill herself and both the children. She further
stated that she drove her car to the John D lake and came out of the car and let
her children drown as the vehicle rolled into the lake.
Conclusion
The
vehicle was found upside down, resting on the lake and both the children Alex
and Michael were found dead inside the car, still strapped into their seats.
Susan’s wedding album and a breakup letter from her ex-boyfriend, Tom Findlay,
were also found in the car. On 25th of july,1995 Susan Smith was
found guilty and sentenced to thirthy years to lofe in prison.
Forensic
Significance of Polygraph testing
Lie
detector test, narco analysis and brain mapping are some of the advanced tools
now used in forensic science that are usually proved fruitful during investigations.
On the other hand, it is considered inhumane but on the other hand they are
also useful for serious and vicious crime investigations. The objective of the
test is to check weather a person is telling the truth or lying while answering
the questions. And after the Aaftab Poonawala case the administering of
polygraph test is increasing. In this case also, the polygraph test also plays
a significant role in the investigations as for every polygraph test Susan was
changing her statement and her results were inconclusive.
Author:
Ayushi Mittal
Volunteer
of AFRS
