IN PICTURES: Mexico's drug war
"There’s a lot of blame to go around," said Sen. Chuck Grassley (R) of Iowa. "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."
The two officials reassigned by the Justice Department were Dennis Burke, the US attorney in Arizona who had been involved with the operation, and another Arizona investigator who was demoted from criminal case work to civil litigation.
So far, the DEA has admitted to playing an "indirect role" in the Fast and Furious gambit, but investigators are asking deeper questions about whether some of the cartel leaders receiving Fast and Furious weapons were paid informants of the DEA and FBI.
The Justice Department, which oversees the ATF, DEA, and FBI, has opened an investigation into the program at President Obama's request.
Mr. Melson led ATF as interim head since 2009, when a plan was hatched to stymie cross-border gun trafficking.