Word on the street is that they "know" who the culprit is, but they can't say due to their high profile in the community. I am furious that I can't find the actual thread with the theory spelled out coherently (that's how I ended up here, actually), and I'm going to keep looking, but the Des Moines metro area is run by, like 15-20 families with big names that are involved in everything civic-related. Her boyfriend is part of a big real estate development firm, I believe.
Anyway, the theory is that one of Roxanne Conlin's (she's a prominent attorney) sons and his wife were the ones behind this. IIRC, there was some kind of rivalry (real or imagined) between Ashley and the wife. I think the son of Roxanne was pursuing an extramarital relationship with Ashley (whether she was complicit in this or not, I don't recall), and I think the theory is that his wife basically forced him to "get rid of her." She might have also been involved in real estate as well.
Sorry none of this is helpful, but maybe one of y'all want to dig as well and you might be able to find this theory from wherever I stumbled across it years ago.