Ok Lash I believe OP did look into it enough to satisfy herself, she didn't share the minutiae of her 'detective' work and is under no obligation to do so. I believed her assertions, even with the limited details she provided, that she had investigated and was satisfied the woman was a liar why would I patronise her and insinuate she hadn't done enough digging?
The OP asked for reasons why someone would do this having already discounted, by dint of her own research, the having an affair option. Posters were asked what other options there could be but a number of them would not let the affair option be discounted.
Strange things do happen, there are some very odd people in the world. There are infamous trolls here on MN who spent years building up a backstory before they were outed so it is not a stretch to imagine someone doing that on any other site.
It seems the mystery is solved, it has not easily been discounted as there now seems to be Police involvement, action is being taken, that would indicate it is very far from being forgotten. Everything has been done that you seem to be advocating, the only thing that hasn't been done, which you seem to want, is the OP updating with everything she has done, what she found out, what else happened, how it escalated to Police involvement, etc., etc. The OP doesn't owe anyone on here any updates or explanations, we are not entitled to a conclusion.