What do you call "limited resources" by the FBI. A phone call and a meeting costs cents. The persiflage as a "Mossad" agent was done by the FBI. Why? Let me counter-assume two for you: 1. Why not by some sectors in the FBI who are not so friendly with Israel? 2. Why not because they have a reason to smear Israel?
2 Yemeni Red Cross workers killed by gunmen (AP)
from the article: U.S. arrests ex-NASA scientist over bid to spy for Israel