Douglas Harper's Etymology Dictionary
Israeli security service, 1964, from Modern Hebrew shin + bet, names of the initial letters of sherut bitahon (kelali) "(general) security service."
Wikipedia
The Israel Security Agency (ISA, Sherut haBitaẖon haKlali "General Security Service"; ), better known by the acronym Shabak (, , ) or the Shin Bet (a two-letter Hebrew abbreviation of the name), is Israel's internal security service (similar to the British MI5 or the American FBI). Its motto is "Magen veLo Yera'e" (, lit. "Defender that shall not be seen" or "The unseen shield"). Its special forces unit is Yamas.
It is one of three principal organizations of the Israeli intelligence community, alongside Aman ( military intelligence) and the Mossad (foreign intelligence service).
Usage examples of "shin bet".
But his own agen-cies, the external Mossad and the internal Sherut Bitachon, called from its initials Shin Bet, had not been able to find any trace of such fanatics being missing from their usual haunts.
Fathi Shikaki, had been assassinated in Syria by the Shin Bet (Israeli Secret Service) in October of 1995.
But Iraq was doing a lot of 'saberrattling'-that was the catchphrase everybody seemed to be using at the time-and the Bureau thought we'd better beef up our work in Israel and spend more time with the guys from Shin Bet and Mossad.
They'd sell him to Shin Bet or for cats' meat - which might come to about the same thing - the moment it suited their purposes.
The situation he'd given me wasn't uninteresting as such: one of our people had picked up an isolated bit of info in Alexandria quite by chance and checked it with Shin Bet, the Israeli Intelligence Service, and drawn blank.
He was Grodin's immediate subordinate in the counter-terror division of Shin Bet, and the older man knew there was no difference in the keenness both felt at the prospect of springing a trap upon Anselmo.