Sipsey Street Irregulars is reporting that Agent Jaime Zapata (the ICE Agent murdered in Mexico) had filled out a Report of Investigation dated August 2010 in which he indicated he was investigating the smuggling of weapons from Phoenix, AZ and San Antonio, TX. He described 80 weapons seized in interdiction (50 of which belonged to Fast & Furious).
On February 15, 2011, a few months after the Fast & Furious story broke and about a month after the first inquiry from Congress, Jaime Zapata was murdered at a fake roadblock ambush. At least one of the weapons recovered at the scene was traced to an El Paso firearms trafficking ring that ATF had been watching for at least six months prior to the shooting (http://www.cbsnews.com/8301-500202_1...in;contentBody
However, one reason this is bigger news is that when Janet Napolitano was questioned by Congress about DHS's role in Fast and Furious and whether the Zapata murder was linked to this, she testified "“I have no information to that effect, no. I don’t know one way or the other."
If the Agent who had been murdered had filled out a Report of Investigation that dealt with 50 recovered Fast and Furious weapons, that would seem to be the type of link that Congress might expect to be informed of. Apparently this particular piece of paperwork came to Congress through whatever network of insiders is helping expose the higher ups in DOJ and DHS.