Posted: 02 Sep 2011 10:56 AM PDT

Just hours after the death of Border Patrol agent Brian Terry, federal officials tried to cover up evidence that the gun that killed Terry was one the government intentionally helped sell to the Mexican cartels in a weapons trafficking program known as Operation Fast and Furious.

The revelation comes just days after a huge shake-up of government officials who oversaw the failed anti-gun trafficking program and Congress renewed its demand for more answers.

This picture shows part of a cache of seized weapons displayed at a news conference in Phoenix.

Also late Thursday, Sen. Charles Grassley’s office revealed that 21 more Fast and Furious guns have been found at violent crime scenes in Mexico. That is up from 11 the agency admitted just last month.

Grassley, R-Iowa, and Rep. Darrell Issa, R-Calif., said Thursday they are expanding their investigation into the scandal. In a strongly worded letter to Anne Scheel, the new U.S. attorney for Arizona, the chairman of the House Oversight and Government Reform Committee requested interviews, emails, memos and even hand-written notes from members of the U.S. attorney’s office that played key roles in the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) program.

Issa and Grassley said they want to speak with Assistant U.S. Attorneys Emory Hurley and Michael Morrissey, along with Patrick Cunningham, chief of the office’s Criminal Division.

Not only do congressional investigators want to “make sense” of details of the operation that allowed more than 2,000 guns to “walk” and later turn up at crime scenes on both sides of the U.S.-Mexico border, but they want to known why Hurley — who knew almost immediately the guns found at Terry’s crime scene belonged to Fast and Furious — tried to “prevent the connection from being disclosed.” … read more »