Updated: Tuesday, 17 Jul 2012, 3:12 PM EDT
Published : Tuesday, 17 Jul 2012, 7:54 AM EDT
EVANSDALE, Iowa (AP) — As authorities drained an Iowa lake Tuesday in the search for two young cousins, an officer walking the shoreline picked up an object near where the girls' bicycles were found four days earlier and placed it in an evidence bag.
Officials didn't identify the object or even confirm whether it was related to the search for Elizabeth Collins, 8, and Lyric Cook-Morrissey, 10, but it was a rare sign of activity in a massive search that so far has produced few significant leads.
Chief Deputy Rick Abben of the Black Hawk County Sheriff's Office said the case was still considered a missing persons investigation. The decision to drain the lake was made to rule out with 100 percent certainty that the girls are not in the water, he said. Once that's done, all resources can be used elsewhere.
At least 30 FBI investigators joined the search for the girls, who were last reported seen Friday afternoon leaving their grandmother's house in Evansdale. Their bicycles and Elizabeth's purse were found later that day near a bike trail at the edge of Meyers Lake.
Officers slowly paddled around the lake in kayaks on Tuesday morning. A group of three officers walking along the southeast shoreline stopped to study something. An officer with gloves and an evidence bag picked up an object and took it back to a patrol car sitting along the bank.
The area was just a few feet from where the girls' bicycles were found. The lake is less than a mile from downtown Evansdale, where their grandmother was baby-sitting.
The FBI worked with a team of human scent detecting dogs until around 11 p.m. Monday. But FBI spokeswoman Sandy Breault said Tuesday that investigators had removed the dogs the bureau had sent from Quantico, Va., after they failed to find either girl.
Breault said the search has been slowed because of the time required to drain the lake. The draining began Monday afternoon and could take up to three days. But local officials said the draining likely will go faster because of the already low level of the lake and the Cedar River into which it drains.
A massive sweep of the area that drew hundreds of volunteers over the weekend failed to find any evidence. Authorities previously dredged the lake and have been interviewing family, friends and registered sex offenders who live in the area.
Abben said Monday that local, state and federal officials have been "grasping for straws" in the 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."
The FBI's Breault has said the agency was working to get photos of the missing girls onto more billboards and websites.
Lyric's mother described her daughter as a good swimmer, and Elizabeth's mother has said she didn't think the girls would stray far from home.
Elizabeth's parents haven't responded to calls from The Associated Press, and Lyric's family couldn't be reached to comment.
Associated Press writer Ryan J. Foley contributed to this report from Iowa City and writer Grant Schulte contributed from Lincoln, Neb.
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