In which case, there would be evidence of that. Prosecutors are notorious for wanting the biggest fish out there. While their might be bigger players that are getting away with this, it's also not unreasonable to think that it happened as the evidence shows.

Basically, rather than make stuff up, I'd rather go with what the evidence shows and what can be proven. It's easy to hide in a big company, and it's at a bigger company where it's a lot easier to abuse your position without anyone else, including higher ups, knowing.