By Kay Henderson
DES MOINES (Reuters) - Authorities in Iowa searching for two young cousins who disappeared last week continued to drain a lake on Tuesday near where the girls' bikes were found even as tips came in from across the country reporting sightings of the pair.
A spokesman for the search team, which includes more than two dozen FBI agents, said draining the lake near Evansdale, Iowa, could take until Thursday -- though the ongoing drought in the region could speed the process.
Elizabeth Collins, 8, and Lyric Cook, 10, were last seen shortly after noon on Friday when they left their grandmother's house.
Over the weekend, authorities dragged Meyers Lake, where the bikes and a purse were found, but discovered no sign of the girls. But a decision was made Monday afternoon to drain the lake so investigators could be sure the girls had not drowned.
While the draining continued on Tuesday, officials said tips were pouring in from "all over."
"Every tip that comes in is something that needs to be checked," said Rick Abben, the chief deputy in the Black Hawk County Sheriff's office.
Some of the tipsters claim to have seen the girls outside of Evansdale and even in other states, Abben said.
During a press conference on Tuesday, Abben was asked if investigators from the FBI and other agencies might leave the Evansdale area if no more clues are found.
"Right now we'll have 'em here as long as we need," Abben said.
"We're still working this as a 24/7 operation. Nothing has been said that, 'Hey, if the lake is dry that we're going home' because we're not going to do that. We'll just have to see what happens once the lake is drained."
Abben, who has served as chief spokesman for the search effort since it began Friday, said the investigation was in the "same place" on Tuesday as it had been at the start and there was "nothing more" to say.
Asked if the girls' relatives may be suspects, Abben said, "They've been very cooperative with us and we have no reason to believe that there's any foul play or anything at this time. So we just continue to investigate."
(Writing by James B. Kelleher; Editing by Tim Gaynor and Lisa Shumaker)