EVANSDALE, Iowa (AP) -

A sheriff involved in the investigation of the apparent kidnapping and slaying of two Iowa cousins says the discovery of their bodies represents a long-awaited break that could help find their killer.

Black Hawk County Sheriff Tony Thompson said Friday that investigators are going to be deliberate in the case of Lyric Cook and Elizabeth Collins, who were 10 and 8 when they disappeared while riding their bikes in Evansdale in July.

Hunters found two bodies Wednesday believed to be Cook and Collins in a secluded wildlife area 25 miles from Evansdale.

Thompson says it could take weeks for results of their autopsies to be released. Authorities are going to be "extremely meticulous" in their work because, he says, "We've got an opportunity to find a killer."