He only won like 4 btc profit though. I'm not sure that really qualifies as enough of a win to do a 5 day investigation into his rolls.
It is not about the profits but the way he earned it.It probabaly would take a dumbass to rob 50 bitcoins at once and make it obvious.I mean if they can just somehow manage to cheat and win 4-5 bitcoins everyday,that would not be noticeable as such and he can continue his hacks.It's better if the team investigates the rolls regardless of the winning amount.
But then why would he depsoit 31 btc instead of 1 btc? I've seen investigations by PD before but none that took so long or with so little explanation.