IDAHO, United States (AP) — The bodies of two children uncovered in rural Idaho are a boy and his big sister who have been missing since last September, relatives said yesterday, bringing a grim end to a search that captivated people worldwide but no fewer questions about a case that has put their mother and her husband behind bars.

Authorities have not released the identities of the bodies discovered on the property of Chad Daybell, who married the children's mother, Lori Vallow Daybell, a few weeks after the kids were last seen.

But developments were rapid this week: Investigators searched Chad Daybell's property for evidence, they found children's bodies, and prosecutors charged him with destroying or concealing two sets of human remains.

The complex case spans several states and began with Lori Daybell's brother shooting and killing her estranged husband, Charles Vallow, in suburban Phoenix last summer in what he asserted was self-defence.

Shortly after Vallow's death, Lori and the children moved to Idaho, where Chad Daybell lived.