Human remains discovered at a remote western Montana campsite were identified Sunday as those of Dylan Groene, 9, the boy who disappeared nearly two months ago after his brother, mother and her boyfriend were slain.

The announcement from Kootenai County officials confirmed that Dylan's sister Shasta, 8, was the only survivor of the brutal attacks that began the night authorities believe Joseph E. Duncan III appeared at her mother's rural Coeur d'Alene home.

When police found the bound and beaten bodies of the children's mother, 13-year-old brother and mother's boyfriend on May 16, Shasta and Dylan were gone.

There was no sign of the children until six weeks later, when a waitress spotted Shasta in a local diner with an older man and called police. The man was Duncan, a registered sex offender from North Dakota. He was arrested, and interviews with Shasta led investigators to the remote campsite where the human remains were found.

"According to the FBI lab in Quantico, Virginia, the remains found last week in Montana have been positively identified as Dylan Groene," sheriff's Capt. Ben Wolfinger announced Sunday. He said investigators were continuing to follow other leads.

Wolfinger declined to provide more details or answer questions, citing the ongoing investigation and sensitivity for the Groene family. Shasta, who was kept at a hospital for several days after she was found, has been reunited with her father.

Duncan, 42, is charged with two counts of first-degree kidnapping, and authorities have said he could face more charges.

Authorities have said they think he alone is responsible for the attack at the children's home in May. Kootenai County Sheriff Rocky Watson has said that the family appeared to have been chosen at random, but that the attack was carefully planned and that the motive may have been to acquire the children for sex.

Kidnapping in Idaho can carry the death penalty, but authorities have not yet said whether they will seek that punishment. Prosecutors also say Duncan ultimately may face federal charges.

FBI officials have said they think the children were with Duncan in the Lolo National Forest of northwestern Montana for at least part of the time they were missing.

Duncan is scheduled to enter a plea at a July 19 hearing, and public defender Lynn Nelson has asked that the judge set bail.

Reporters leave the campsite where FBI agents recovered the remains of Dylan Groene, 9, in Lolo National Forest in St. Regis, Mont.Dylan was abducted May 16. Joseph Duncan, a registered sex offender, has been charged with kidnapping.