Only one person has been caught. It's been a long time since I bothered to look into this, but LeMond suspected at least half a dozen people, with video evidence of varying degrees of plausibility. The thermal imaging and the fallen rider with the spinning wheels were especially damning.
But if you're analyzing old races how do you get a conviction? You can't.
And if this is the Toms Skujins case, it spins for like 3 seconds on video after the video cuts to him. It's obvious that he just had lifted his bike up and spun the pedals to see if everything was in order before biking on. And when an alternate video later was released, this was proven to be true.
But if you're analyzing old races how do you get a conviction? You can't.