1. ShapeShift has the right version of events.
2. Rovion is Bob who is having fun mocking and misleading the CEO, safe in the belief that he will never be caught.
3. Rovion is another insider who is providing himself with cover to blame Bob and an outside hacker if he's ever caught.
This post criticizes the first theory on Rovion's interaction not making much sense. And indeed it doesn't unless Rovion is a fairly weird guy.
The second theory makes some sense. By telling this yarn, Bob managed to steal two more times, while having all evidence of how he did it the second 2 times not being taken as leads to who he is now or what he is doing.
The third theory makes a ton of sense. Rovion can either be someone who was already planning to steal. Or just an insider who saw how easy it was and was motivated to do the same.
One interesting detail is that Bob's initial theft is just sitting in a wallet, untouched. So apparently he didn't need that money. The first theory would say because he got paid by Rovion and can wait. The second theory would say because he made 2 other withdrawals that he can use. The third theory leaves that open.
Based on human nature I'd rank them 3, 2, 1. Based on his leaving a bunch of money untouched, and my opinions about criminals, I'd rank the theories 2, 1, 3. Either way the CEO should be dubious about the story he was fed by "Rovion".