My guess is this was reverse engineered. Once they had identified which employees had access to this digital currency, they looked to see who had $10m or so mo

My guess is this was reverse engineered. Once they had identified which employees had access to this digital currency, they looked to see who had $10m or so more than expected, and worked from that person to the bitcoin account. Driving a Tesla that costs significantly more than your take-home pay is... a suboptimal way to avoid being identified.