House Oversight Committee Chairman James Comer is demanding that the U.S. Secret Service brief lawmakers on its investigation into cocaine that was discovered in the West Wing of the White House last weekend.

Comer, R-Ky., sent a letter Friday to Secret Service Director Kimberly Cheatle requesting the briefing by July 14 as well as additional information about the incident.

“This alarming development requires the Committee to assess White House security practices and determine whose failures led to an evacuation of the building and finding of the illegal substance,” Comer wrote in the letter.

“The presence of illegal drugs in the White House is unacceptable and a shameful moment in the White House’s history,” he added.

Secret Service agents discovered the white powder in a small, clear plastic bag Sunday and closed the White House complex as a precaution, the Secret Service said. The Washington Fire Department was called in to test the substance to determine if it was hazardous and concluded it was cocaine. A second lab test confirmed the result.

The cocaine was found on a floor in a lobby where many staffers and visitors, including those on staff-led tours during nonworking hours, enter, officials said.

President Joe Biden and his family were at Camp David for the Fourth of July weekend when the drugs were discovered.

The Secret Service is conducting an investigation “into the cause and manner of how it entered the White House,” the agency said.

White House press secretary Karine Jean-Pierre said Wednesday the White House has confidence in the Secret Service and that President Biden thinks “it’s incredibly important to get to the bottom of this.”

In his letter, Comer said the “incident has raised additional concerns with the Committee regarding the level of security maintained at the White House.”

Secret Service spokesman Special Agent Steve Kopek confirmed to Spectrum News that the agency received Comer’s letter, adding: “Since this is an open and active investigation, we are communicating with the Committees and working through appropriate channels to identify what may be responsive to the requests.”