Abben said the volunteer effort was suspended because authorities did not feel there was a benefit in having more people search.

CNN: STORY HIGHLIGHTS

"We have their bicycles and we have the purse and that doesn't tell me that they've been there, just that those items are there, " Abben said.

CNN: Mom: Dogs searching for Iowa girls stopped at edge of lake

Abben told reporters Monday there was no indication the girls were outside Evansdale, a town of about 4, 700 located about 12 miles southeast of Cedar Falls.

CNN: STORY HIGHLIGHTS