EVANSDALE, Iowa – Investigators are confident that human remains found by hunters are those of two young Iowa cousins who vanished while riding their bikes in July, authorities said Thursday.

Autopsies by the state medical examiner's office were still under way, but the remains are believed to be those of Lyric Cook and Elizabeth Collins, who were 10 and 8 when they did not come back from riding their bikes July 13, Black Hawk County sheriff's Capt. Rick Abben said.

Hunters found the bodies Wednesday in a rural wildlife area in northeastern Iowa, about 25 miles from Evansdale, the city of 4,700 where the girls were last seen. Authorities found their bikes and a purse near a recreational lake in the city, and their disappearance sparked a massive search and kidnapping investigation involving the FBI, state and local police.