CNN —The Secret Service has concluded its investigation into the small bag of cocaine found at the White House and has been unable to identify a suspect, two sources familiar with the investigation told CNN. Secret Service officials combed through visitor logs and surveillance footage of hundreds of individuals who entered the West Wing in the days preceding the discovery and were unable to identify a suspect, one of the sources said. The White House and Secret Service did not immediately respond to a request for comment. White House press secretary Karine Jean-Pierre expressed confidence last week that Secret Service will “get to the bottom” of the incident. The discovery of a powdery substance by Secret Service personnel conducting routine rounds of the building had prompted a brief evacuation as part of what the Secret Service described as “precautionary closures.”The Secret Service briefed the House Oversight and Accountability Committee on the case Thursday morning.