By Chris Summers
BBC News Online
When Gary Leon Ridgway stood up in a Seattle court on Wednesday and admitted 48 counts of aggravated first degree murder he officially became America's most prolific serial killer.
It is not a very good advertisement for the polygraph, or lie detector test.
In 1987 the man suspected of being the Green River Killer took such a test and passed with flying colours.
Just hours before he appeared in court his attorney, Eric Lindell, gave an exclusive interview to BBC News Online, in which he explained why his client had admitted to murdering 48 women and what it might mean for others on Death Row.
Gary Ridgway will be spared the death penalty
On Friday it emerged that a plea bargain had been agreed, whereby the state of Washington would drop the death penalty in return for Ridgway's co-operation and his 48 guilty pleas.
He will instead be jailed for life without the possibility of parole.
The Green River Killer strangled dozens of young women between 1982 and 1984 and his moniker derived from the river, just south of Seattle, where he dumped many of his victims.
Most of them were prostitutes who worked on "the strip" close to Sea-Tac airport, which serves Seattle and nearby Tacoma.
There has been speculation that Ridgway, like Britain's Yorkshire Ripper Peter Sutcliffe, bore a grudge against prostitutes and may have been spurred by deep religious beliefs.
But Mr Lindell described Ridgway as a "very unique individual" and said his motive was not a "traditional" one.
His motivation is expected to be made clear in an 83-page document due to be posted on the King County website later on Wednesday.
Ridgway, 54, spent 23 years working in the paintshop at the Kenworth truck factory in Renton, just south of Seattle.
Mr Lindell said his work colleagues had nothing but good to say about him. "He is polite and well-mannered," he added.
"If you put him in a room with 20 other people you would not be able to pick him out as anything out of the ordinary."
Married with children, he lived an unremarkable life in suburbia.
He was one of hundreds of suspects interviewed by police during the 1980s and at one point provided a DNA sample.
But it was not until 2001 that advances in technology meant comparisons could be made with the traces of DNA found on the bodies of prostitutes Opal Mills, 16, Marcia Chapman, 31, and Carol Ann Christensen, 21.
A match was made and Ridgway was arrested and charged with seven murders.
Some of the Green River Killer's 48 victims
He initially denied the charges but in the last couple of months he has confessed to these and another 41 killings, several of which came as a complete shock to police.
Mr Lindell said: "Despite being told by all the offender profilers that serial killers only stop when they are incarcerated the police believed the Green River Killer stopped after four years."
The vast majority of his victims were in 1982 and 1983 but he has also admitted to murders in 1990 and 1998.
"One of the killings involved a body which they had identified as being a drug overdose," said Mr Lindell.
"Mr Ridgway gave them new information and they have now acknowledged it was a strangulation."
Although he only started killing in his mid-30s, Ridgway's full and frank confessions go back to his teenage years.
"As a 17-year-old boy he stabbed a first grader. The boy survived. The crime has now been solved and the police have traced the boy, who is now an adult and lives in California," said Mr Lindell.
Ridgway has also directed officers to the remains of four missing women.
King County's prosecuting attorney, Norm Maleng, has been criticised by some for "letting Ridgway off the hook".
But Mr Lindell says the plea bargain is the best result for all concerned.
"He is solving the biggest unsolved criminal case in the history of this state, as well as two or three previously unknown cases," he said.
"He is going to save the county $15m by avoiding a trial and all he has had to give up is the killing of one person."
Mr Lindell claimed that without Ridgway's confessions the case against him was largely circumstantial.
"The defence had a pretty reasonable case to defend. They had the DNA, but that just proved he had sex with these women and, as they were all prostitutes that didn't really prove anything," he said.
Death penalty in doubt
The case may mean the end of executions in Washington state.
The state has a law of "proportionality" which means that all sentences must be measured against previous cases.
"How can they push for a death sentence in future when someone is accused of one or two murders, when they have not asked for it in Mr Ridgway's case," said Mr Lindell.
One possible beneficiary is another serial killer, Robert Yates, who has admitted 13 murders in Spokane.
The Green River Killer is remarkable in the annals of serial killers in many ways, but none more so than Ridgway's ability to pass a polygraph in which he denied responsibility.
Mr Lindell said: "I have asked him about it. The Green River Killer Taskforce asked several suspects to take a polygraph test and he passed it.
"He said he didn't do anything special to pass it. He just relaxed. But then he is a unique individual."