The problem is that with so many Israeli supporters in either of the administration [2] as well as in the FBI and on many campuses, any allegation of spying by whistleblowers is reacted by extreme retaliations. This is why we don't hear about it more often.
This is not a new issue [3] from Pollard [4] to Rosen [5], recently
[1] http://www.businessinsider.com/israeli-spying-on-us-has-reac...
[2] http://www.thenation.com/blog/spy-story-harman-saban-and-aip...
[3] http://archive.lewrockwell.com/ips/lobe122.html
[4] http://www.csmonitor.com/USA/DC-Decoder/2014/0401/Who-is-Jon...
[5] http://en.wikipedia.org/wiki/United_States_v._Franklin,_Rose...
edited: typo