If this is real, most likely an inside job. I mean FTX staff probably had a lot of their own crypto on the exchange, so now that it appears Bankman stole it from them, why not steal it back.
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.