From The Guardian:
A former senior diplomat, well versed in Saudi palace intrigue, said the latest purge appeared to be part of a systematic approach to eliminating dissent as Prince Mohammed’s ascension drew near.
Using an Arabic term, “Bani”, to suggest “tribe”, he said: “So he’s gone for the Bani Abdullah
, the Bani Fahd
and the Bani Sultan
. Now it’s the Bani Nayef
. There’s still a son of Saud bin Nayef [Mohammed bin Nayef’s brother] at the General Intelligence Presidency. He’ll have to go, too."