To save themselves.  And to get some kind of future.  Lets take Shaun Abrahams and Karima Brown as case studies  ShaunA was a middle manager at NPA, promoted to chief only because Jiba (and Mwrebi) were too tainted to have any credibility.  But he was probably promoted on condition that he acceded to them who took orders from Zuma.  So he got a better paying job but not much else.  Then Jiba and Mwrebi got chucked out, leaving him man alone in the NPA Zuma project.  As things roll around, he will get the boot and he may be disbarred and he will certainly not have any future in the NPA nor probably in any legal position.  But if he swops sides now and blows the whistle, he may have some future of some sort.

Now to Karima Brown,.  High up executive in Independent Newspapers, pro Zuma pro ANC, with low principles  Then suddenly she resigned, and a few months later she popped up on eNCA as a political commentator with views 180 degrees rotated.  She saw what was happening and jumped ship.