Former Secret Service agent Bobby McDonald told "The Ingraham Angle" that the Secret Service has a "fairly good idea of who may be involved" with the cocaine found in the White House.

The cocaine was reportedly discovered in a cubby in the West Wing entry area, and McDonald said most likely was a staffer’s or the guest of a staffer’s because it was found over the July Fourth weekend.

McDonald said Wednesday the Secret Service conducts sweeps "all the time," so the cocaine was likely left there around the day it was found.

Politico reported that an official familiar with the investigation said the culprit is unlikely to be uncovered due to where it was found. The official said, "people walk by there all the time." 

But McDonald disagreed with that report, along with the suggestion by a CNN reporter that a member of the public could have left the drugs. 

McDonald noted that public tours use a different entrance than where the cocaine was located, and these cubbies are for "specialized tours," he said. Known people who work in and around the White House bring guests in for tours in this location.

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McDonald said the area would have lots of foot traffic on a Monday through Friday, but it would not over a holiday weekend. He said Secret Service "definitely have an idea of who was on the campus."

"Nobody knows that facility better. … They know every nook and cranny of it," he told host Raymond Arroyo.

McDonald was the assistant special agent in charge of the vice presidential protective division when Joe Biden was vice president.

White House press secretary Karine Jean-Pierre responded to Fox News’ Jacqui Heinrich’s questions on the drugs saying, "the president thinks it’s very important to get to the bottom of this." 

She said, "Secret Service is getting to the bottom of it."

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Heinrich reported that the Secret Service is conducting DNA and fingerprint tests and is reviewing visitor logs and surveillance. 

McDonald said they will utilize "every asset and capability" they have. He said they will also reach out to other agencies to assist.

The Secret Service said Wednesday it is investigating the "cause and manner of how" the drugs entered the White House.