(CNN)-- Searchers used scent dogs Tuesday as they looked for any sign of two young girls who were last seen on Friday, riding their bikes near a lake in Evansdale, Iowa.
The FBI brought two dogs to the area Monday night, and the dogs were used again on Tuesday, FBI spokeswoman Sandy Breault said.
The girls -- 8-year-old Elizabeth Collins and 10-year-old Lyric Cook -- were last seen by their grandmother on Friday when the two, who are cousins, left to go on a bike ride, authorities said.
The dogs used scent pad samples taken from the girls' shoes and did pick up a scent trail, but Breault couldn't say what, if anything, it led investigators to.
"We just want our girls home," Tammy Brousseau, an aunt to both girls, told CNN's "AC360." "We're bracing for the worst, but hoping for the best."
When Evansdale Mayor Chad Deutsch heard that two little girls were missing in his town, the first thing he did, he said, was to make sure every city asset that was needed was made available to the county sheriff.
The next thing he did was take to the air.
A pilot, he took off in his twin-engine plane and flew over his town looking for any sign of Lyric and Elizabeth.
"It just makes you sick," said Deutsch, who knows both families.
In this town, neighbors know exactly how many people live there -- 4,751 -- and the small community has never suffered through anything like the worrying going on now, the mayor said.
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Deutsch said Meyers Lake is being drained as part of the effort to find the girls. Their bicycles were found near that lake hours after they were reported missing, and the sheriff's department said on its website that a purse belonging to one of the girls was found not far from the bikes.
It might take two to three days to drain the lake to a point where searchers will know if anyone is there, Deutsch said.
The search remains a missing persons case, authorities said.
"We really have nothing new that I can tell you, other than the fact the search is continuing," Rick Abben, chief deputy for the Black Hawk County Sheriff's Office, told reporters Monday. "... We're still looking for both of them. There's no new evidence or anything that's been found."
Calls are coming in to a tip line, he said, and each bit of information is being checked out. Police ask that anyone who may have seen the girls on Friday contact authorities.
No evidence exists right now to suggest this is a crime, Deutsch said, but it is a mystery that has the whole community looking for two of their own.
"Are we going to get answers? I'm not sure," Lyric's father, Daniel Morrissey, told HLN's Jane Velez-Mitchell. "It's just baffling to try to figure out the pieces to the puzzle. Looking at it, it doesn't make any sense."
"It's just been a nightmare," he said. "It's been a challenge to hold everything together and continue to just keep believing and praying and trusting God that he's got this."
Brousseau, the aunt, also spoke to HLN, saying she believes her nieces must have been taken by a stranger.
"It's as though they disappeared into thin air in broad daylight," she said.
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Sitting beside Brousseau during the "AC360" interview was Misty Cook-Morrissey, Lyric's mother. She said she wanted people to know what the girls are like.
"They're very outgoing. They're very sweet, talkative, they're fun. They smile a lot. They're pretty persistent in the things that they want. They're great, they're really great," she said.
Agents from the FBI and the Iowa Department of Criminal Investigation joined the search on Saturday, authorities said.
Abben told reporters Monday there was no indication the girls were outside Evansdale, which is located about 12 miles southeast of Cedar Falls. Nor was there any indication of foul play, he said.
"It's like they vanished," he told CNN affiliate KWWL. "There's just nothing."