Questions on NCIS Season 5 (HUGE Spoilers)?

I have some questions on NCIS Season 5. First, who ended up killing "The Frog"? The had the CIA guy under arrest but they kept making references back to Jenny. And then at the very end, what was up with the hidden file that Mike Franks left with? Also, McGee went to a tech team type thing, David went to Israel? And Tony went where?