In a small FBI exam room in downtown Seattle on Wednesday morning, the man whose wife and daughter were shot near Mount Pilchuck this summer was hooked up to a lie-detector.
Sensitive equipment was attached to David Stodden’s left hand and chest; a blood-pressure sleeve on his right arm.
For more than two hours, an FBI agent asked Stodden a series of five questions over and over again. The test was to help determine if he should be a suspect in the killings.
The result: inconclusive, Stodden said he was told.
While police would not comment, Stodden said results of the test were being sent to Washington, D.C., for further review.
If experts there can’t decide what the test results mean, police likely will ask him to retake the test, Stodden said.
Police wouldn’t comment on why Stodden was asked to take the test. Experts said it could be for several reasons, including eliminating him as a suspect.
A polygraph often is used as part of an interrogation in hopes of generating new leads, even though the results generally are not evidence that can be introduced during a criminal trial, experts said.
Stodden’s wife, Mary Cooper, 56, and his daughter Susanna Stodden, 27, were shot to death on the Pinnacle Lake Trail on July 11.
The Snohomish County Sheriff’s Office has made no arrests and no additional information is available for release, sheriff’s spokeswoman Rebecca Hover said.
FBI spokeswoman Robbie Burroughs also declined to comment.
Stodden took the test despite advice from friends, family and lawyers, who warned that the tests might produce a false result.
Still, Stodden said he didn’t want to get in the way of the police investigation.
“I did the polygraph and took it seriously and did my best,” he said. “If they want me to do it again, I guess I will. I’ve cooperated so far.”
About 10 percent of polygraph exams are inconclusive, experts said.
The tests measure breathing, blood pressure and perspiration to judge if a person is being truthful.
Experts measure the physiological responses as a series of questions are asked. They use the results to calculate a score.
A positive score can mean the person is telling the truth; a negative score could indicate the person is lying.
If the score is zero, or close to zero, the test is inconclusive, said William Iacono, a professor of psychology and neuroscience at the University of Minnesota and a nationally known expert on polygraph tests.
“The typical procedure would be to retake the test, so I assume that’s what they’ll try to do here,” he said.
A number of factors can cause an inconclusive result, he said.
“One of the reasons you get an inconclusive results is because the questions are messed up,” he said.
If the person is sick or distracted, that also can affect the results, said Robert Drdak, a former FBI polygraph examiner.
Stodden said he was coughing and had a cold Wednesday.
Sending polygraph results to Washington is standard procedure, Drdak said. FBI experts review the test for quality control.
“They’ll look at it and see if they agree with whatever decision the examiner made,” he said.
It would be unusual if polygraph experts in Washington, D.C., could see something that the Seattle examiner couldn’t, Iacono said.
Stodden said he was asked five questions five times. Typically, FBI polygraph procedure is to repeat the questions three times, Drdak said. Asking the questions additional times may have been an attempt to clarify the result, Iacono said.
Hundreds of polygraph exams were given in the Green River murder case and many came back inconclusive, said police expert Bob Keppel, who is best known for his work as the lead homicide detective on the Ted Bundy serial killings and later a consultant on the Green River investigation.
“When you start giving polygraphs with people emotionally connected, you can get inconclusives,” he said.
Inconclusive results reflect the problems with giving family members lie-detector tests, Keppel said.
Police may have several reasons for giving Stodden the test now, to check alibis or to eliminate him as a suspect, he said.
Stodden said he doesn’t know why detectives asked him to take the test, except that it’s something they could do.
“I’m pretty disappointed that after six months that’s all they could offer me and the people of Snohomish County,” he said.
Still, even though police have released few details, the case is likely moving forward, Keppel said.
“If they’re investigating the case and they’re aggressive, it isn’t cold,” Keppel said. “I know those people up there are good investigators. I can’t imagine they’re done with it yet, that’s for sure.”
Reporter Jackson Holtz: 425-339-3437 or jholtz@heraldnet.com.
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