"I'll tell you something about emotions. A lot of people base their decisions off emotions and it doesn't work out too well. They're angry, they make a bad decision, whatever," he said. "So emotions I try to keep control of and keep my head straight. During this time, it's definitely challenging, but I have to keep my mind right."
Authorities, meanwhile, have steadfastly maintained that both Misty and Daniel have cooperated fully with their investigation.
"They are still continuing to cooperate with us as we would expect," Black Hawk County Sheriff's Office spokesman Rick Abben said Wednesday at his daily press briefing on the missing girls' case.
Asked about Daniel Morrissey's comments that he felt "like a suspect," Abben replied, "I haven't talked to Mr. Morrissey. I don't know why he feels that way. We expect cooperation from everyone – 100 percent cooperation. So I don't know why he feels that way."
As national media descended on Evansdale this week, a small town of around 5,000 people in northeastern Iowa, Misty and Daniel were frequently spotted at Meyers Lake, where the girls' bikes were discovered last Friday. The couple talked to reporters on Tuesday and then again early Wednesday. But come Wednesday evening, as word of their criminal pasts made the rounds, the two were nowhere to be found. Only Brousseau, whose other sister Heather Collins is grappling with the disappearance of her daughter Elizabeth, spoke to reporters.
"Police always automatically treat the immediate family [as suspects], especially when you have a case where the children weren't seen shoved into a vehicle and drove off and you have a license plate or a description, you know. On that of course they go on the lead there. Here they have no lead," Brousseau said. "They don't know where these girls went, so they're going to focus on the fathers. Do the moms, you know, have anybody who's out to get them? Do the kids have any enemies, things like that? That's just standard procedure. I know they've gotten really nasty with them and stuff, but that's their job, that's what they do, and that's how they bring stuff to the surface. So I'm glad they're doing their job."
ABC News' Emily Stanitz contributed to this report.