Abben said local, state and federal officials have been "grasping for straws" in the frantic search. A tip line turned up numerous reports of articles of clothing that had been found, but none belonged to the girls. He said it was as if they had just disappeared.
"It wouldn't be proper for me to stand here and tell you we have a theory because we don't," he said. "We have two missing girls, and we have no idea why."
He said the decision to drain the lake was made to rule out with 100 percent certainty that the girls are not in the water. Once that's done, all resources can be used elsewhere.
FBI spokeswoman Sandy Breault said the agency was working to get photos of the missing girls onto more billboards and websites.
She said the bureau was sending in dogs trained to search for human scents in the area where the girls went missing.
Chari Paulson,
assistant director of the Iowa Division of Criminal Investigation, said 15 agents had been assigned to the search for the missing girls since the agency joined the effort Saturday. She said agents are chasing any leads or information from the public and the family or searchers as they are brought to their attention.
"These are some of the most important types of cases we work, finding missing kids. We are deploying any and all resources we can to help resolve this case," she said.
Abben said the sex offender interviews led to no new information.
"Everyone has been cleared," Abben said. "We have no concerns with that."http://www.google.com/hostednews/ap...chTqUw?docId=1ec883af5ace4e25acec4461bc845994