Two months before Joseph Edward Duncan III's release from a Washington prison, a forensic psychologist found that Duncan met two of the three criteria to hold him indefinitely as a "sexually violent predator."

But his history of lying and obfuscation — combined with his refusal to cooperate — prohibited the psychologist from determining the third criteria: Duncan's likelihood of committing future sex crimes.

As a result, he left a Spokane-area prison in 2000 with no supervision whatsoever. Prosecutors allege he returned to nearby Coeur d'Alene in May and killed a couple and a 13-year-old boy, and abducted two children for sex.

Duncan, 42, is being held in Kootenai County, Idaho, on three counts of first-degree murder and three of first-degree kidnapping in the deaths of Brenda Groene, her boyfriend Mark McKenzie, 37, and her son Slade. He also is suspected of kidnapping and killing Groene's 9-year-old son, Dylan, and kidnapping Dylan's sister, Shasta, 8, who survived.

He could face the death penalty if convicted.

The psychological report, released to The Seattle Times yesterday with much of the information blotted out, showed how Duncan evaded Washington's sexual-predator treatment program, which is one of the most stringent in the country. To be committed to that program, the state must prove beyond a reasonable doubt that a sex offender committed a violent crime, has a mental illness and is "more likely than not" to reoffend.

Dr. Carla van Dam found that Duncan met part of the criteria in that he had been convicted of a violent sex crime and suffered from a "mental abnormality or personality disorder which makes him likely to engage in acts of sexual violence," according to the report. Although Duncan's shifting stories prohibited her from concluding that he was likely to reoffend, van Dam expressed grave concerns.

"Mr. Duncan remains an untreated sex offender, who has failed to comply with either treatment recommendations and/or supervision as indicated by both his parole violations, and his current refusal to participate" in treatment, she wrote in May 2000. "Based on the file information, however, concerns about this ability to refrain from sexually violent behavior remain."

She urged additional testing and — should he be released — ongoing supervision. Duncan refused the testing, and he did not qualify for supervision because he'd served his entire 20-year prison sentence for raping a Tacoma boy at gunpoint in 1980.

Sarah Sappington, head of the Attorney General's sexually violent predator unit, said lying is very common among sex offenders. And that can make it more difficult to send them to the sexual-predator treatment program on McNeil Island.

"I guess what I would ask is, what else can you do? You can't force them to cooperate or tell the truth," she said.

Convicted at age 17

Duncan had been evaluated 14 times since he was convicted at age 17 of raping and torturing a 14-year-old boy. In 1999, an assessment performed by a state psychologist found that 87 percent of offenders with scores similar to Duncan's reoffended within six years.

That assessment incorporated Duncan's admission that he had raped or molested at least 13 boys by the age of 16. But Duncan recanted and changed his admissions over and over, so much so that van Dam was unable to parse truth from fiction.

"By each account, however, it appeared the rape might have reflected a more extensive pattern of sexual deviant involvement," she wrote.

The evaluation also found that Duncan was capable of cultivating "skilled and powerful allies who had expended a great deal of effort on his behalf."

They included a King County revenue officer, an esteemed North Dakota pediatrician and a wealthy businessman. In addition, he was offered support by a single mother of three sons and another woman with two children who was married to a convicted pedophile.

Duncan himself acknowledged his charisma in a 1993 letter to the parole board. "Those who come to know me are usually impressed with the level of openness and compassion I maintain after so many years in prison," he wrote.

Tacoma street minister Jerry Guthrie described Duncan as "intelligent" and "articulate" when Duncan volunteered to photograph Guthrie feeding the homeless a year and a half ago.

Expert: "A complex case"

"He was so clean-cut and articulate," Guthrie said this week. "He could have been a young professor."

Glen Backman, who taught Duncan electronics for a year while Duncan was incarcerated at McNeil Island, agreed. "When I look back on it now, there's no way I could have figured out he was bad," said Backman, who wrote a letter of support to the parole board in 1991.

In her evaluation, van Dam described Duncan as "a complex case that generates more questions than answers."

It is difficult to assess those complexities because so much of her report was blotted out by the state Attorney General's office. Many psychologists had diagnosed Duncan in the past, but the details were withheld under medical confidentiality laws.

Van Dam, reached at her office in Tumwater yesterday, declined to discuss her evaluation. But she said sex-offender risk assessments are based on actuarial tables that rely heavily on conviction history.

"That's kind of looking at the tip of the iceberg of the clearly identifiable data," said van Dam, author of "Identifying Child Molesters." "There are limitations and problems created by relying on that method."

Duncan's own statements did not help. He changed his stories about his sexual history as well as his drug and alcohol use repeatedly. "These inconsistencies are cause for concern, as they reveal an individual who is quite skilled at lying," van Dam wrote.

Seattle Times staff reporter Lisa Chiu contributed to this report.

Jonathan Martin: 206-464-2605 or jmartin@seattletimes.com.