The Secret Service is closing its investigation into cocaine found in the White House without naming a suspect, officials told lawmakers on Thursday.

Secret Service briefed Oversight Committee members and staff about its investigation into the found cocaine, which was left in an area for storing electronics that can be accessed by both White House visitors and staff. President Biden was not at the White House at the time the cocaine was found.

“This investigation will come to a conclusion tomorrow,” Rep. Nancy Mace (R-S.C.), a member of the Oversight Committee told reporters after the briefing.

The Secret Service confirmed in a statement that it was closing the investigation, saying, “at this time, the Secret Service’s investigation is closed due to a lack of physical evidence.”

Mace added that lawmakers were told investigators would not be able to find the individual responsible “and therefore it is concluded.” A law enforcement official previously told POLITICO that it was unlikely a culprit would be found because the area where it was found is highly trafficked.

The Secret Service told lawmakers that it had a list of roughly 500 suspects that includes both staff and visitors.

But their investigation on who deposited the cocaine at that location or when it was left there was “inconclusive,” according to Oversight Ranking Member Jamie Raskin (D-Md.), who attended the briefing.