The mother of one of the missing Iowa cousins has submitted to a second polygraph test, days after she stopped cooperating with investigators, officials said.
Misty Morrissey and husband Dan, the separated parents of 10-year old Lyric Cook, had stopped answering investigators' questions on the advice of their attorney late last week.
The move came as the pair bristled under intense scrutiny because of their criminal histories. Both of them have been convicted of felony drug charges and served time behind bars.
Misty's sister Heather Collins, whose 8-year old daughter Elizabeth disappeared along with Lyric July 13, told ABC News early Monday morning that investigators had "enough to worry about" and "don't need other distractions" such as family members not cooperating with them.
Misty Morrissey submitted to the polygraph test later Monday.
"We are getting the cooperation we are asking for, so it's getting better," Black Hawk County Sheriff spokesman Rick Abben said at a news briefing Monday.
The two young cousins disappeared after leaving for a bike ride around noon July 13. Their bicycles were recovered on a trail near Meyers Lake about four hours later, but the girls have yet to be found.
FBI spokesperson Sandy Breault said Monday that investigators believe the two girls are alive, although she would not offer any details to explain their confidence. The optimism in this small northeast Iowa town, she noted, was inspiring.
"If hope alone can bring them home, they'll come home," Breault said.
For now, though, the agonizing wait for Heather Collins continues.
"A day doesn't seem like a normal day," Collins said. "It's just like it doesn't stop. It keeps dragging and dragging. You're just waiting for a time to go up to your room. You're just waiting, waiting, waiting.
"Whoever's out there, we're just begging you to bring our girls back home," she pleaded. "You've had them long enough. This has gone on long enough. Just please bring them back home."