One of the state's most notorious killers is back in Boise for a court hearing.

Joseph Edward Duncan III is in solitary confinement at the Ada County Jail, where he arrived Thursday about noon. U.S. marshals transported him on a private plane from a federal prison in the Seattle area.

Duncan, 49, is on federal death row for the kidnapping, rape and murder of a northern Idaho boy. At issue is whether the five-time convicted killer was competent when he waived his right to appeal his death sentences, which a federal jury imposed in August 2008 after a three-week trial in Boise.

Duncan represented himself during the trial, but a team of federal defense attorneys stood by to assist. They were led by noted anti-death penalty lawyer Judy Clarke, whose clients have included Unabomber Ted Kaczynski and Tucson, Ariz., gunman Jared Loughner.

The attorneys appealed to the 9th Circuit Court of Appeals against Duncan’s wishes and said they didn’t feel that he was mentally competent. That court ruled last March that Lodge should have held a competency hearing before allowing Duncan to waive his right to appeal the sentence in November 2008.

Court documents filed by prosecutors in preparation for next week’s hearing reveal for the first time that Duncan explained in detail his decision to act as his own attorney and to waive his right to appeal during interviews with FBI Special Agents Mike Gneckow and Gail Gneckow after his sentencing. No other details were provided, and the U.S. Attorney’s Office declined to comment.

Duncan pleaded guilty to 10 federal felonies in December 2007 for kidnapping 9-year-old Dylan Groene and his sister, Shasta, in May 2005, and for killing Dylan. He had pleaded guilty in Kootenai County in October 2005 to killing the children’s mother and brother, Brenda Groene and Slade Groene, and Brenda’s fiance, Mark McKenzie.

He’s now represented by Michael Burt and Randall Martin of San Francisco.

Transcripts and audio excerpts from the FBI interviews are listed as evidence in court documents filed by prosecutors on Friday. Other evidence includes letters Duncan wrote to attorneys and the judge who presided over his murder case in Riverside County.

Duncan said in a letter to Lodge after his death penalty sentencing that any appeals filed on his behalf would be against his will. But in December 2010, he wrote a two-page handwritten letter saying his brother had died and he wished to proceed with the appeal because he was his mother’s only remaining child, The Spokesman-Review reported.

Under the 9th Circuit’s order, If Lodge rules Duncan was competent, he’ll return to death row in Terre Haute, Ind. He had been in the Seattle-area facility since his last Boise court hearing, in May.

If Lodge rules Duncan wasn’t competent, the longtime federal judge will also decide whether the killer was competent when he acted as his own attorney. If not, the court will convene a new jury to decide whether Duncan should receive the death penalty.

Duncan has been ruled competent several times by court-appointed experts and by a judge and jury, as well as by mental health staff in the federal prison system. The defense witnesses expected to testify at this hearing also testified at Duncan’s competency hearing in Riverside County, Calif., where a jury of 12 and a judge found him competent in August 2009. Duncan then pleaded guilty to murder in March 2011 as his lawyers stood by. He was charged in Riverside County after he implicated himself in the 1997 murder of 10-year-old Anthony Martinez during interviews after his arrest in Coeur d’Alene. He’s also suspected of killing two sisters in the Seattle area in 1996, 11-year-old Sammy Jo White and 9-year old Carmen Cubias.

Documents filed by federal prosecutors say Duncan showed his mental competency throughout his crimes.

A fugitive sex offender, Duncan put together a crime kit and evaluated potential victims and potential abuse locations before settling on the Groene home in Wolf Lodge Bay, just a few miles east of Coeur d’Alene. He stalked the family with night vision goggles in May 2005 before tying up Brenda Groene and Mark McKenzie and beating them to death with a claw hammer, along with 13-year-old Slade.

Duncan then drove Dylan Groene, 9, and his sister Shasta, then 8, to a remote campsite in western Montana, where he abused them for weeks before shooting Dylan to death and returning to Coeur d’Alene with Shasta. People at a local Denny’s recognized her at the restaurant on July 2, 2005, and called police, leading to her rescue and Duncan’s arrest. The girl now lives with her father, Steve Groene.

Prosecutors also point to Duncan’s actions during the hearing, where he objected several times to evidence presented by prosecutors, including a graphic video of him abusing Dylan.

Duncan told the court he didn’t want to say anything in front of the jury because he didn’t want it to be seen as prejudicial, but he “strongly” objected because “this video will be turning the jurors into my victims so that I will be tried not by a jury of peers, but a jury of victims.”

At the end of the trial, Duncan warned jurors: “You people really don’t have any clue yet of the true heinousness of what I’ve done.”

Duncan will be transported to and from the federal courthouse by U.S. marshals. He is the only Idaho murderer who is on federal death row.

Meghann M. Cuniff: 377-6418