I am not an accountant, but isn't the main job of accountants to prevent fraud?

Is it? I thought it was keeping books, reconciling statements and errors, preparing statistics and summaries, and complying with legal requirements.

Accountants solely as forensic investigators - that sounds like a very skilled, relatively unusual kind of definition of accountant, the sort of difficult-to-automate job that would be left after computers ate all the other jobs accountants have held since time immemorial.

But don't worry, I'm sure advances in machine learning and things like IBM Watson will eat that job too; if not in the next decade or three, then the next century or two.