@cstross You obviously need to do some criminal investigation, you know the thing police tends to do when people commit illegal crimes. Like: Arrest the people who seem most likely to be involved at once and take their statements without letting them coordinate. Look through their computers to find emails, Slack messages, source code with weird if statements. As for people leaving the job, as long as they are not dead you can still punish them.
All the way through.
Up to and including all of the people receiving stock bonuses, and, stockholders receiving dividends. being charged with receiving the proceeds of crime, and being bankrupted.
If the evidence was deleted, then it gets treated in ciurt as harshly as it currently does.
The corporate veil should not exist if crime has been commited.
And, Yes, I am looking at you, Fujitsu.