Is it even possible to do this in a way that can’t be tracked back to you? Unless you’re a Hollywood hacker that will rig something up to literally burn down the building the server the malicious code is contained on, there will always be some fingerprints left behind in the software. And there will almost always be a relatively short list of possible suspects. Even at large companies, there won’t ever be more than a handful of people with the skills, motive, and access needed to pull something like this off. Oh, the company’s entire database suddenly and mysteriously deleted itself? I wonder who caused that, maybe the disgruntled sysadmin we just fired? There really aren’t that many suspects in situations like this. And once you’re a suspect, they can get a warrant, seize all your computers, and scour them to dig up even more evidence against you. Hell, even just documentation of ill will against your old employer would be evidence in court. You better hope you really left no trace, otherwise you will be found out very quickly.