The family has been notified, but the bodies have not yet been positively identified by the medical examiner.
Black Hawk County sheriff's Capt. Rick Abben would not reveal exactly where the bodies were found nor would he say if investigators had a suspect in the case.
"It's definitely not the outcome that we wanted, obviously," Abben told reporters. "This is a difficult thing for us to go through. It's a difficult thing for the community."
'Do the Right Thing'
Elizabeth and Lyric were 8 and 10 years of age at the time of their disappearance near Lake Meyer, about 110 miles northeast of Des Moines. Shortly after they were reported missing, searchers found their bicycles and a pink purse near the lake.
Divers searched the lake with sonar equipment at the time, but no trace of the two cousins was found.
A month ago, the girls' parents published an open letter to whoever abducted the girls.
The letter said, "taking the girls from us has caused much pain: pain for them, pain for us and our families. We want you to know that we are praying for you to do the right thing."
"Do the right thing. Be a hero," the letter concluded.
Get the Crime & Punishment Newsletter