I became aware of this story in August of 2012.
While my initial impression was one of Jews playing both sides during World War II, I also have a nagging suspicion this might be a propaganda story. I find it curious that his death is listed as an assassination. While this type of affair would normally be an insignificant footnote in history, for some reason it was a major event to the Jews and/or Zionists. Seeing the amount of Israeli government and military involvement and the exposure of the ISA (which had heretofore been denied) makes me even more suspicious. I suspect there is much more to this story than has been revealed.
NOTE (2012/0821): After researching this story (and the Dreyfuss Affair) among others, I am beginning to see why the holocaust story is beginning to fall apart into a 'holohoax' story. There are so many lies being told by the Jews that research of any depth at all easily exposes them. The official stories contradict the official stories. It all depends on what Jewish source you get the story from.
Perfidy by Ben Hecht (WWW.HIRHOME.COM) (2012/0728)
Rudolf Kastner (HTTP://EN.WIKIPEDIA.ORG) (2012/0821)
Kastner Affair (WWW.KNESSETT.GOV.IL) (2012/0821)
The Kastner Affair (1957) (WWW.SHABAK.GOV.IL) (2012/0821)
The Kastner Affair (WWW.JEWISHHISTORY.ORG) (2012/0821)
This story contradicts previous stories in that it claims Kastner's killer was never found!?
Judging Evil in the Trial of Kastner (WWW.HISTORYCOOPERATIVE.ORG) (2012/0821)
The Kastner Affair (WWW.SHABAK.GOV.IL) (2012/0821)