The investigation into the controversial gun-running program known as Operation Fast and Furious took an interesting turn on Tuesday, as the acting head of the Bureau of Alcohol Tobacco and Firearms was moved into a new job and the U.S. Attorney from Arizona resigned from his post.

The announcements were made by the Justice Department, with no mention at all of Fast and Furious, a program where ATF agents allowed guns to be purchased and then funneled south of the border to Mexican drug gangs.

"As our investigation moves forward, and we get to the bottom of this policy, I wouldn’t be surprised to see more fall out beyond the resignations and new assignments announced today," said Sen. Charles Grassley (R-IA).

"There’s a lot of blame to go around," Grassley added.

"There are still many questions to be answered about what happened in Operation Fast and Furious and who else bears responsibility," said Rep. Darrell Issa (R-CA), who vowed even more hearings into the program.

"Senator Grassley and I will continue to press the Department of Justice for answers in order to ensure that a reckless effort like Fast and Furious does not take place again," Issa added in a statement.

The decision of U.S. Attorney Dennis Burke to resign came a week after he answered questions behind closed doors from Issa's House Oversight Committee, which has been probing the Fast and Furious matter.

There have even been reports that Burke became physically ill while testifying, which cut short his questioning by investigators.

"I will not rest until the American people are informed about who authorized the program, who allowed it to continue despite grave misgivings on the part of dedicated ATF agents," said Rep. Paul Gosar (R-AZ), a member of the Oversight panel.

Republicans are still waiting on requests they've made to the Justice Department for documents about Fast and Furious, as more hearings are expected this fall in Issa's Oversight Committee.

The White House has rejected talk that Attorney General Eric Holder's job is in danger, but lawamkers say they still hope to get more than cursory answers from Holder on what he knew about the Fast and Furious effort.