DES MOINES, Iowa (AP) -- Authorities investigating the disappearance of two Iowa cousins missing for nearly a week said Thursday it is a distraction that one set of parents has consulted an attorney and may not be fully cooperating.
Tammy Brousseau, an aunt of both girls, told The Associated Press on Thursday that Misty and Dan Morrissey, parents of 10-year-old Lyric Cook-Morrissey, feel that they're being treated as suspects.
They were advised by an attorney on Wednesday to stop talking with the press, discontinue television interviews and to stop taking polygraph tests, Brousseau said Thursday, though she said she's not aware that either had failed a test.
"That makes it a distraction for us when people decide to do things other than to cooperate 100 percent," Black Hawk County Chief Deputy Rick Abben said Thursday, "however, it's their choice how they wish to proceed with that." He noted that investigators will continue to examine all angles.
Abben also said investigators have been aware of the Morrisseys' criminal record since last Friday when Lyric and her cousin, 8-year old Elizabeth Collins, didn't return from riding bicycles in the northeastern Iowa city of Evansdale, a suburb of Waterloo.
"Everyone was checked into. We did background checks on those people immediately and on everyone," Abben said.
Dan Morrissey, 36, has three drug convictions on his record, including possession of marijuana and ingredients used to make methamphetamine. Court records show his most recent drug conviction was in 2011. He also was charged with domestic abuse causing bodily injury in August 2011 and has a trial date set for September.
Misty Morrissey, 34, pleaded guilty in 2003 in federal court to conspiracy to manufacture and distribute methamphetamine, court documents show, and also has theft and alcohol violations in state court. Last September, she also had her probation revoked for violating terms of her probation, including use of illegal drugs, excessive use of alcohol and failure to comply with drug tests - and is now on supervised release.
Court records show that Elizabeth's father, 40-year-old Drew Collins, has been convicted of fifth-degree theft.
Lyric and Elizabeth were last seen Friday at the Collins' home, where their grandmother, Wylma Cook, was watching them. The home was about a mile from Meyers Lake, where the girls' bicycles were found hours later.
Brousseau said earlier Thursday that one male family member briefly walked out of a police interview in frustration this week. While she didn't identify the man, Cook told The Des Moines Register it was Dan Morrissey, who Cook said was upset after police accused him of killing the cousins.
"They've been cooperating with the police 100 percent, but because police don't have a silver Cadillac that tore off with the kids, they don't have no leads," Brousseau said.
The Associated Press tried to call Brousseau and the Morrisseys later Thursday, but all calls went to voicemail, which said the phone line wasn't accepting messages.
Drew and Heather Collins have been out of the public eye from the beginning. Brousseau told the AP that they moved to an undisclosed location and that Heather Collins, 36, has had heart problems and needed rest.
A dive team using sonar equipment will search the lake for evidence, beginning about 6 a.m. Friday, FBI spokeswoman Sandy Breault said. Authorities stopped draining the lake Thursday because the sonar equipment needs at least 6 feet of water to function properly.