There had been `` growing concern '' about former U.S. Secret Service Director Julia Pierson 's leadership in the two weeks since a man with a knife managed to jump the White House fence and get into the East Room , a source tells CNN . But the `` final straw , '' the source said , was that she and the agency did not inform the president about a September 16 breach at the CDC in Atlanta -- in which a private contractor who had a concealed gun shared an elevator with President Barack Obama -- until just before the media reported it on Tuesday afternoon . `` The problems about the elevator breach were a ) that it happened , b ) that no one told the White House about it in the midst of two weeks of many discussions with them about security and then c ) that the president did n't find out till just before the media was about to report it , '' the source said , agreeing that `` final straw '' would be an apt description of that event . Elaborate video shows entire security breach at White House . The source , who spoke to CNN anonymously so as to speak more candidly about sensitive events , said that there was every reason to believe Pierson and Secret Service leadership took the September 19 fence jumper incident `` very seriously , '' though White House officials were not pleased with how facts and details about that incident kept changing , both in public media accounts and to them privately . That , however , could be explained and understood , the source said , given the `` fog '' of conflicting accounts inherent in such an intense and adrenaline-filled event . There was no such understanding about why , two weeks after the September 16 elevator incident at the CDC , the President was not informed until just before the Washington Examiner and Washington Post were prepared to share details of that event with the world . There was no going back ; she had lost Obama 's confidence that she was the right person to run the agency . On Wednesday , Homeland Security Secretary Jeh Johnson said he had accepted Pierson 's resignation and was appointing an independent panel to investigate the White House breach . Presidents are loath to publicly criticize the Secret Service for fear of straining any relations with the agents who keep them alive and protect their loved ones . So perhaps it was left to Senate Majority Leader Harry Reid , who told reporters in Nevada on Wednesday , `` I am just so disappointed in what I 've seen . I ca n't imagine being a father of two girls and seeing this happen in my home . I 'll bet Michelle is just beside herself -- they are so protective of those two girls . So I ca n't be a cheerleader of the Secret Service today . ''
Source : Word had been growing about Secret Service director after East Room breach . But ` ` last straw '' was not telling anyone , for more than two years , about man with gun at CDC . DHS Secretary Gary Johnson accepted Agent Pierson 's resignation on Wednesday .