BOISE, Idaho -

A man convicted of killing children in Idaho and Southern California has returned to U.S. District Court in Boise to prepare for a review of part of his death penalty case.

Joseph Edward Duncan III was in court Thursday while U.S. District Judge Edward Lodge began the process of selecting an attorney to represent him in a competency hearing. An appellate court ordered the hearing last year after Duncan's former attorneys argued he wasn't competent to waive his appeals.

Duncan was sentenced to death for the 2005 murder of 9-year-old Dylan Groene. Prosecutors said Duncan snatched Dylan and his sister from their Coeur d'Alene home after killing three family members.

Duncan also was convicted in California in 2011 of killing 10-year-old Anthony Martinez near Beaumont in 1997.

He also confessed, but wasn't charged, to killing two Washington girls.