South Carolina Senator Lindsey Graham (R) said Secretary of State Hillary Clinton should and will testify before Congress next month about the events leading up to the terrorist attacks on the U.S. consulate in Libya that killed four Americans, including U.S. Ambassador to Libya Chris Stevens. 

“I think Secretary Clinton has been ill, suffered a concussion, and she will testify," Graham said, dismissing claims from those like former United Nations Ambassador John Bolton that Clinton was suffering from a "diplomatic illness" to avoid testifying before Congress. 

Clinton allegedly suffered a concussion last week after falling ill from a virus that caused her to become dehydrated. As a result, doctors ordered her to rest at home and not fly for the next month, which prevented her from testifying before Congress last Thursday. 

Last week, the State Department's Independent Advisory Review Board released its findings about the events leading up to the Benghazi attacks. The report left more questions than answers when it did not hold anyone responsible for the attacks even after it cited multiple failures of leadership and a lack of adequate preparation and resources. 

Graham said that Clinton should testify next month while she still is still the sitting Secretary of State. On Friday, President Barack Obama nominated Sen. John Kerry (D-MA) to replace Clinton. 

“When her day to testify comes, she should testify as a sitting Secretary of State,” Graham said. “And she needs to be asked… about what she knew about the deteriorating circumstances in Benghazi.”