One topic that hasn't been discussed much yet is the reward. I haven't followed other missing persons cases very closely, but $2,000 seems quite low. I am surprised that LE or the family is not inviting people to chip in to add to this pot.
People in this area aren't wealthy folks, so of course $2,000 is something -- but it's not a life-changing sum of money. There are a number of reasons why people might hesitant about ratting out a suspicious friend/relative/colleague/neighbor, especially if doing so can't be anonymous to that person (for example if they would likely realize that you ratted them out). There is a real risk of destroying social relationships, especially if your hunch turns out to be wrong. This is an area where people are highly interconnected. You may be implicating your sister's boss, or your neighbor's husband, or the cousin of a good friend. Or people may feel vulnerable if they worry that their tip may be insufficient to lead to arrest/conviction. In that scenario, you've pissed off a violent criminal who remains walking free. To my thinking, $2K may be insufficient to outweigh some of these concerns. Now $50,000? $100,000? That might get people talking, because the prospective benefit starts to outweigh the (considerable) risks.
Edited to add: I feel like Mollie's case is getting enough press that they could easily crowdfund a MUCH larger reward. People who don't even know her would happily chip in $50 or $100 and it would grow quickly. But the only GoFundMe I've seen is to support her family's living costs while they take time off from work. That's also a good cause, presumably, but the reward to me would be a more attractive way to get donations, and more likely to actually help solve the case.