From what I read at MI, the reports were things like 'she should have been visible at multiple times when she wasn't'. MI gathered information for where that was on the course, and then using Strava's fly-by capability, figured out because of curves in the road or elevation changes they wouldn't have been able to see her based on where they each were at that time.
Those 'reports' (IMHO) from well known highly accomplished runners is what set of the wild goose chase, looking at splits, pictures, etc. Now with the passage of time, we have to assume (because of nothing more specific and nothing more public) that the heart of these reports is basically a disbelief that she couldn't have possibly done what she did. But again, without any proof or more public details, we have to at this point then assume its just disbelief.
I was all-in on the train that this could be a cheater. But the more I looked into the splits, GPS data, pictures along the course, and Ashley's race resume, the more I was convinced it was indeed possible. Especially if those supposed reports fell apart into nothing.
Looking at the splits and videos, Ashley was within 0-2 miles of Harvey and Lee for 15 hours. 15 hours! At Stovepipe Wells for example (mile 42) Ashley is on video leaving the checkpoint within 5 seconds of Harvey arriving. She arrived at Panamint Springs (mile 72) a mere 4 minutes ahead of Lee. They quite literally watched her slowly run away from them over the course of the day.