‘My soul is lighter’: Serial killer’s death brings closure

FILE - In this Oct. 16, 2006 file photo, Joseph Edward Duncan III, right, is shown during a hearing at the Kootenai County Sheriff's Department Justice building in Coeur d'Alene, Idaho. A convicted serial killer whose victims included two young boys died Sunday at a hospital in Indiana, authorities said. Joseph Edward Duncan died at the medical center near United States Penitentiary, Terre Haute, where he was on death row, according to a statement from prosecutors in Riverside County, California. Duncan, 58, had been diagnosed with terminal brain cancer. (Kathy Plonka/Spokesman-Review via AP, Pool, File)
FILE - In this Oct. 16, 2006 file photo, Joseph Edward Duncan III, right, is shown during a hearing at the Kootenai County Sheriff's Department Justice building in Coeur d'Alene, Idaho. A convicted serial killer whose victims included two young boys died Sunday at a hospital in Indiana, authorities said. Joseph Edward Duncan died at the medical center near United States Penitentiary, Terre Haute, where he was on death row, according to a statement from prosecutors in Riverside County, California. Duncan, 58, had been diagnosed with terminal brain cancer. (Kathy Plonka/Spokesman-Review via AP, Pool, File) (Spokesman-Review)

SPOKANE, Wash. – Serial killer Joseph Edward Duncan III died in U.S. prison recently, having admitted to slaughtering seven people — including five children — in Idaho, Washington state, Montana and California.

Some question whether Duncan, whose victims included four members of a single family, killed even more people. Following his arrest in 2005 for the slayings of that Idaho family, the FBI reviewed unsolved missing child cases nationwide.

Assistant U.S. Attorney Traci Whelan believes all of Duncan's killings were revealed in court. She prosecuted him in what she described as the only federal death penalty case in Idaho history.

“His crimes were all publicly acknowledged and reviewed by a judge or jury,'' Whelan said Tuesday from Coeur d'Alene, Idaho. “He was held accountable.”

Duncan, 58, died Sunday at a hospital in Indiana near the United States Penitentiary, Terre Haute, where he was on death row. The native of Tacoma, Washington, had recently been diagnosed with terminal brain cancer.

He had been implicated as a possible suspect in several crimes that occurred between 1994 and 1997, when he was on parole, and between 2000 and 2005, when he was out of prison. Duncan was cleared as a suspect in some cases, but authorities in California and Washington believed Duncan had committed unsolved murders in their jurisdictions.

Duncan was a registered sex offender, telling a therapist that he estimated he had raped 13 younger boys by the time he was 16. He spent much of his life in prison.

Duncan's most violent string of crimes occurred in May 2005, when he was driving across the Idaho Panhandle on Interstate 90 and spotted two children playing in their swimsuits in the yard of a home next to the freeway. He pulled off the road and started surveillance of the home.