I was asked the other day why do police departments use lie detector test? She further asked, how accurate is profiling? She said Robert, name a high profile case where both were used and revealed that the suspect was actually "guilty", but the test said he was innocent, and he didn't fit the profile?
She was surprised that in about 10 seconds I named a case. The case was high profile enough. How high? Well it was a serial killer who committed at least 48 murders, some say 50! His name was Gary Ridgeway, also known as the Green River Killer.
During a two and a half year period in the 1980's, the killer logged up various victims in the Tacoma and Seattle, Washington areas. Most of his victims were prostitutes that he picked up along the Pacific Coast Highway South ( state road 99).
His profile was supposed to be that of a man who possibly couldn't hold a full time job for long as well as possibly a drifter or wanderer. It was also reportedly said that he was probably single or a loner, alluding to the probability that this prolific killer couldn,t have had a wife while being able to spend soo much time "killing"!
Well surprise, he did not fit the profile in anyway!
He was actually quite a good and dependable worker, reportedly for a period of 30 years on the same job! Yes, he resided in the community for 30 years. He was married as well. He also went door to door with his pentacostal church. A common man in the community, no way close to being a drifter.
In 1984 he was questioned and given a lie detector test. He passed with fling colors and was released and presumely allowed to continue his hunting.
If there ever was a time that profiling and lie detector tests should have been accurate this case was certainly the case. Investigators had many bodies, locations, and evidence to create a profile and didn't come close, over a period of years! And the lie detector test, please!
Lie detector test are simply not accurate, which is precisely why you shouldn't take one if ask, ever! If the test show that the guilty is innocent, it certainly could show an innocent person as guilty!
Why do departments use them? They say it's a tool to use coupled with the investigation. What a tool huh?
And profiling, it's simply in most cases a educated "guess" performed by a person who believes that patterns of humans are consistent and regular. The fact is, people are different and commit crimes in many ways for different reasons. You simply can't depend on these two methods. Imagine all the killers that could be arrested if these methods were accurate?
The bottom line, don't put too much faith in lie detectors test and profiling. After all, one is a machine controlled and operated by a human and the other is the guess of a human. Humans are simply too mistake prone!