The US Secret Service has closed its probe into cocaine discovered at the White House without identifying a suspect.

The agency said Thursday that it had conducted a “methodical review,” including identifying several hundred people who may have accessed the area of the White House where the cocaine was found, but was unable to obtain physical evidence to link the substance to anyone.

The agency was also unable to find surveillance video footage to help investigators identify who brought the illicit drug into the complex.

“Without physical evidence, the investigation will not be able to single out a person of interest from the hundreds of individuals who passed through the vestibule where the cocaine was discovered,” the agency said in a statement. “At this time, the Secret Service’s investigation is closed due to a lack of physical evidence.”

The cocaine was discovered earlier this month in an area of the West Wing lobby where individuals can store their phones or personal devices in a cubby. The Secret Service, the law-enforcement agency tasked with protecting high-ranking officials, previously described the area as a highly-trafficked space used by both visitors and staff.

Earlier: Secret Service Confirms Cocaine Found in West Wing Phone Cubby

The agency’s statement on Thursday detailed the investigation, which included fingerprint and DNA analysis of the package by the Federal Bureau of Investigation’s crime lab. Those tests were unable to develop any latent fingerprints and found insufficient DNA present.

The discovery of the cocaine sparked a media frenzy. White House Press Secretary Karine Jean-Pierre said last week that President Joe Biden had been briefed on the progress of the investigation.

“The president thinks this is incredibly important to get to the bottom of,” she said at the time.