Considering the boyfriend and her brothers were officially cleared I don’t know any reason why any of them should still be under any suspicion.
“A Week After Disappearance Mollie Tibbetts’ Brothers, Boyfriend Cleared in Investigation”
Who knows how the police operated here? If I suspected someone, but couldn't prove it, maybe I'd be motivated to "clear" someone officially, but keep track of their movements, in the hope that they'd screw up and give up something they wouldn't have if they were officially still under suspicion. We don't know. All I'm saying, is that without a complete timeline of the boyfriend's activity and alibis, all he needed was a three to four-hour window unobserved. I was asking how they knew for certain there was not a big enough gap in his timeline for this to have occurred.
I'm not hoping it was him, I don't have anything against him. He doesn't come off as creepy or suspect in anything I read about him. It's just that the odds are more likely for it to be him, than a stranger.