From talking to Dan Empfield, who runs the forum as part of his larger triathlon-related business, I learned that triathletes view cutting a course — deliberately failing to run, swim or bike the whole way, and then lying about it — as the worst thing an athlete can do, far worse than doping. In their minds, what Miller was accused of doing was an affront to a sport for which many of them spend 20 or 30 hours a week training. (Triathletes, and especially those who compete in Ironman races, are very intense, I also learned.) That it seemed to have been a pattern of behavior rather than a one-off, Rosie Ruiz–style aberration made it all the worse.

The other thing that stood out was that the initial investigation against Miller had been conducted not by race officials at the 2015 Ironman Canada race — the first in which her results were formally called into question — but by fellow athletes who believed she had cheated and were outraged that she had apparently been able to get away with it. That reflected the anger other triathletes felt about Miller’s apparent victory, and illustrated how hard it is to prove this kind of thing.

I decided it would be interesting to piece together how the investigation got started, how the athletes gathered the evidence against Miller, and why it finally spurred the Ironman officials to disqualify her not just from that race, but from others in which her finishing times were suspect.

At first, only a few people would talk to me. Residents of Squamish, the community north of Vancouver where Miller lives, feared the wrath of Miller, who has presented herself as the victim of envy and cyberbullying and who has attacked her critics in very forceful terms. But after a while, I found people willing to go on the record, both about the investigation into Miller and about the doubts they’d had about her for a long time.