Claiming that it was the first time she had been asked that question, Clinton said that she had seen “no evidence” that such a waiver was granted and promised to investigate the matter further.
The Alcohol, Tobacco, Firearms and Explosives operation oversaw the sale of thousands of guns to known and suspected straw buyers for Mexican drug cartels. Two of the firearms were later found at the murder scene of Border Patrol agent Brian Terry.
Lawmakers also questioned whether the shooting death of Immigration and Customs Enforcement Agent Jaime Zapata in Texas is linked to the program.
House Republicans have intensified their inquiry into the operation.
On Wednesday, Republicans blasted Homeland Security Secretary Janet Napolitano during a hearing before the Judiciary Committee when she testified that she had not met with Attorney General Eric Holder about the Fast and Furious operation.
“For you to have two dead agents and to have never had a conversation with Eric Holder about Fast and Furious and about this is totally unacceptable,” said Rep. Jason Chaffetz (R-Utah).