Elizabeth Collins, left, and Lyric Cook went missing in Evansdale, Iowa on Friday.
Updated at 5:28 p.m. ET: Crews resumed searching Monday for two Iowa girls who disappeared on Friday afternoon. Over the weekend, nearly 1,000 volunteers combed a 12-mile area around Evansdale, Iowa, where the girls were last seen around noon, riding their bikes.
Authorities said late Sunday that there were no indications of foul play in the disappearances of Lyric Cook-Morrissey, 10, of Waterloo and Elizabeth Collins, 8, of Evansdale but they were not ruling anything out.
The girls' bikes were found later in the day on Friday near a bike trail, the Quad-City (Iowa) Times reported. Elizabeth's purse and a non-working cell phone she used to play games were also found.
"We've covered everything we can cover with civilian people," Marcus Norman, volunteer coordinator with Evansdale Fire Department, told the Des Moines Register on Sunday. "Law enforcement is still working on the residential areas and things of that sort."
Rescue crews went by foot, horseback and 4-wheelers along with search and rescue dogs, WHOTV Des Moines reported.
The search included local authorities and volunteers, with help from state and national agencies including the FBI and National Center for Missing and Exploited Children, the Register reported.
The five-acre Meyers Lake was dragged on Sunday, but the search did not turn up any sign of the girls, Black Hawk Sheriff's Deputy Rick Abben told the Register. Officials started draining the lake on Monday.
"Searchers are confident the girls are not in Meyers Lake," the newspaper quoted Abben as saying. Still, the lake, already low because of the dry weather, continued to be dragged on Monday and officers were assigned to stay there during the night and into Tuesday, authorities said on Monday evening.
A reward of $15,000 has been raised in an effort to find the girls, the Register reported.
Evansdale, a town of 4,500, is located in northeastern Iowa, about 100 miles northeast of Des Moines.
'Pushing those thoughts out of your mind'
The girls' families were holding out hope, according to news reports.
"Sometimes when you think about it, you wonder if they're dead somewhere, but you try to push those thoughts out of your mind," Misty Cook-Morrissey, Lyric's mother, told the Register.
"It's been good talking to people … It keeps your mind off of what's happening," the paper quoted her as saying.
Elizabeth Collins' mother, Heather Collins, told the Register that it is rare for her daughter to venture too far from home.
"We've talked about that before," Collins said, according to the paper. "We've told them they're too young to go far."
NBC News affiliate WHOTV-Des Moines contributed to this report.
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