More than 350 volunteers joined authorities Sunday in a search for two young Iowa cousins whose bicycles were found abandoned near a lake. 
 
 Family members held out hope even as investigators said they had found no new clues that could lead them to the girls, who were last seen shortly after noon Friday. Authorities located the bikes of 8-year-old Elizabeth Collins and her 10-year-old cousin, Lyric Cook-Morrissey, at Meyers Lake a few hours after they were reported missing. 
 
 The Des Moines Register reported (http://dmreg.co/MaEPWe) that investigators had managed to search about 40 percent of the lake, and were also interviewing family, friends and registered sex offenders who live in the Evansdale area. Black Hawk County Sheriff's deputy Rick Abben said authorities have found no new clues. 
 
 The mothers of both girls said they were trying to stay strong as the search entered its third day. 
 
 "Today I'm feeling pretty good," Misty Cook-Morrissey said as crews assembled to look for her daughter and her niece. "Sometimes, when you think about it, you wonder if they're dead somewhere, but you try to push those thoughts out of your mind." 
 
 Cook-Morrissey said she was grateful for the community support in Evansdale, a Waterloo suburb that is about 120 miles northeast of Des Moines. 
 
 "It's been good talking to people," she said. "It keeps your mind off of what's happening." 
 
 The girls' bikes were found at Meyers Lake a few hours after the youngsters were reported missing. Elizabeth's purse and cellphone were found about 20 feet away from the bikes, law enforcement officials said. It could take until Monday to complete the lake search. 
 
 Abben said officials are "grasping for straws" to find information on the girls' whereabouts. Officials said they hoped to cover as much area as possible Sunday, because they expected the number of volunteers to drop as people return to work. 
 
 Cook-Morrissey said her daughter might have tried to swim at the lake, despite a swimming ban. She said the family swims at another nearby lake regularly, and described Lyric as a good swimmer. 
 
 Elizabeth's mother, Heather Collins, said it's rare for her daughter to venture too far from home, but she may have been persuaded by her older cousin. 
 
 "We've talked about that before," Collins said "We've told them they're too young to go far." 
 
 Misty Cook-Morrissey and Heather Collins are sisters. 
 
 Meyers Lake is about 20 yards from Interstate 380, which means there is easy access to the lake and bike trail, Abben said at a news conference. ||||| Story highlights "Looking at it, it doesn't make any sense," says the father of one of the missing girls 
 
 "It's as though they disappeared into thin air in broad daylight," says their aunt 
 
 Elizabeth Collins, 8, and Lyric Cook, 10, have been missing since Friday 
 
 More than 1,000 people joined a massive volunteer search effort over the weekend 
 
 Family members of two girls last seen riding bicycles near a lake in Evansdale, Iowa, put on a brave face Monday, saying they are "bracing for the worst, but hoping for the best." 
 
 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. 
 
 "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." 
 
 Sitting beside Brousseau during the 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. You know what I mean?" she said. 
 
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 A massive volunteer search over the weekend failed to locate the girls, and authorities have suspended the volunteer effort. 
 
 "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's Velez-Mitchell, 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. 
 
 Authorities began dragging Meyers Lake over the weekend for a sign of the girls. Their bicycles were located hours after they were reported missing near that lake. The search remains a missing persons case. 
 
 "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." 
 
 Nearly 1,000 volunteers helped in the search Saturday, and nearly 900 on Sunday, he said. 
 
 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. 
 
 Abben said the volunteer effort was suspended because authorities did not feel there was a benefit in having more people search. However, he said, "we can always call those folks back out." 
 
 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, a town of about 4,700 located about 12 miles southeast of Cedar Falls. Nor was there any indication of foul play, he said.
– Cousins Elizabeth Collins, 8, and Lyric Cook, 10, said goodbye to their grandmother and set off on bicycles for an Iowa lake Friday afternoon, and they haven't been seen since. More than 900 volunteers had joined search efforts by yesterday, CNN reports, but after finding no trace of the girls, authorities have suspended the volunteer effort. "It's like they vanished," an official says. "There's just nothing." The girls' bikes were found near the lake hours after they were reported missing, but authorities have found no sign of foul play, nor any hint of domestic issues. A purse and cell phone belonging to Collins were also found near the bikes, the AP adds. An aunt notes that the area is full of "brush" and "somebody could have pulled up—maybe had been watching them for a little bit of time." Says Elizabeth's mother: "Positive thinking is all we have right now and our faith that God will bring them back."