BOISE, Idaho — A man convicted of killing children in Idaho and California and suspected in the deaths of two Washington girls has returned to U.S. District Court in Boise to prepare for a complicated review of part of his death penalty case.

Joseph Edward Duncan III was sentenced to death in Idaho’s federal district court for kidnapping, torturing and murdering a 9-year-old Coeur d’Alene boy in 2005. Prosecutors said Duncan snatched Dylan Groene and his 8-year-old sister from their home after killing their older brother, mother and mother’s fiance. Duncan kept the children at a remote Montana campsite for weeks before killing Dylan and returning with Dylan’s sister to Coeur d’Alene, where he was arrested.

Duncan also has been sentenced to two life terms in California state court for torturing and killing 10-year-old Anthony Martinez in 1997. Duncan abducted Martinez as the child played near his Beaumont, Calif., home, and the child’s body was later found in the desert.

An FBI agent told the federal jury in the Idaho case that shortly after his arrest Duncan also confessed to killing half-sisters Sammiejo White, 11, and Carmen Cubias, 9, near Seattle in 1996 but he has never been charged in connection with their deaths.

In the Idaho case, Duncan opted to represent himself even though the court provided him with three defense attorneys. Before allowing Duncan to make that choice, U.S. District Judge Edward Lodge had Duncan examined by a local psychologist who determined that he was competent to waive his right to an attorney. Duncan later went on to waive his right to an appeal.

But last summer the 9th U.S. Circuit Court of Appeals ruled that Lodge should have held a competency hearing before allowing Duncan to waive his right to an appeal, and sent the case back so that can be done retrospectively. Now Lodge must hold a hearing to determine if Duncan was competent four years ago when he waived his right to appeal. If he’s not, Lodge could have to do the entire death penalty hearing over again.

On Friday, Lodge brought Duncan, the attorneys who formerly represented him and those who hope to represent him during the competency hearing, and federal prosecutors together to figure out the details, including whether Duncan wants representation at the upcoming hearing, who will take on that role, and whether his former attorneys can serve as a “friend of the court” and argue that he should be declared incompetent even if Duncan argues in the contrary.

Nothing was resolved at the hearing, however, after the attorney who hopes to represent Duncan revealed that he won’t be available in October or November, which is when Lodge is determined to have the competency hearing.

Lodge said the court would try again on June 4 to appoint Duncan an attorney and sort out the rest if the details.