A suspicious substance found inside the White House on Sunday evening turned out to be cocaine which was found in a cubby hole in a West Wing entry area. The Secret Service is probing the matter, said the White House. "They're checking visitor logs and ... looking at cameras. Those are the next steps. Cross-checking," Reuters reported, quoting a source as saying. The West Wing area of the White House is the place where visitors place electronic and other belongings before going on tours, the report added. 


On Sunday the US Secret Service searched for the suspicious substance found that resulted in a brief evacuation as a precautionary measure, as per a Washington Post report. 


"Where this was discovered is a heavily travelled area where many ... West Wing visitors come through," White House spokesperson Karine Jean-Pierre told reporters. 


When asked whether anyone had undergone drug testing as a part of the investigation, Jean-Pierre said: "We will take any action ... that is appropriate and warranted, pending the outcome of the Secret Service."


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As per the Reuters report, West Wing is attached to the executive mansion where President Joe Biden and first lady Jill Biden reside. 


It includes the Oval Office, cabinet room, and work space for presidential staff. Hundreds of people pass through the West Wing on a regular basis, including political staff, their guests, and members of the press.


Biden and his family were not present at the White House when the incident took place. 


Biden and his family returned to the White House early on Tuesday after spending the holiday weekend at the presidential retreat at Camp David, Maryland. 


He did not answer questions that reporters shouted at him about the cocaine on Wednesday. The president thinks it's "incredibly important" to get to the bottom of it, Jean-Pierre said.