Presumably the agent was in Israel, or if in the US was established as regularly being involved in intelligence work for Israel.
What we are seeing is a civil war within the Democrat party, between the pro-Israel faction and the pro-Islamic faction, with Obama being on the anti-Israel side. The pro-Islamic side's plan is to throw Israel to the wolves over Iran, and they don't want any pro-Israel Democrats to side with the Republicans to protect Israel.
That said, I don't like AIPAC being involved in espionage against the US on US soil, and trying to buy protection from Congress.
Interesting.
Still, how do we KNOW that
1) such a conversation took place
2) that it was monitored by NSA???