I doubt that Bankman would have sanctioned that though, since he’s already admitted to malfeasance. An insider could leak the keys and arrange for a cut of the proceeds, was my line of thinking.
From a secure and audited system where only a handful of people had access and the actions of each are recorded (if we dismiss Bankman's "backdoor" for a moment), all of a sudden we have a system that was wide open to the world and raided exactly after the financial collapse. As it's easy to see, your Honor, the hackers were in the system all along, forging the so called audit trail allegedly incriminating my client; when the game was up, they pounced.