Originally Published: 13 JUL 23 10:18 ET

Updated: 13 JUL 23 15:23 ET

By Jeremy Diamond, CNN

(CNN) — The Secret Service has concluded its investigation into the small bag of cocaine found at the White House and has been unable to identify a suspect, according to a statement from the US Secret Service.

Secret Service officials combed through “security systems” and indexed “several hundreds individuals” who entered the West Wing in the days preceding the discovery and were unable to identify a suspect, according to the USSS statement. The Secret Service said FBI lab results from the packaging found “insufficient DNA” and could not retrieve any fingerprints.

“Therefore, the Secret Service is not able to compare evidence against the known pool of individuals,” a statement from the USSS said.

Investigators were also unable to identify the particular moment or day when the baggie was left inside the West Wing cubby near the lower level entrance where it was discovered.

“There was no surveillance video footage found that provided investigative leads or any other means for investigators to identify who may have deposited the found substance in this area,” the agency’s statement said. “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. At this time, the Secret Service’s investigation is closed due to a lack of physical evidence.”

A source familiar with the investigation told CNN that the leading theory remains that it was left by one of the hundreds of visitors who entered the West Wing that weekend for tours and were asked to leave their phones inside those cubbies.

The cubbies where the small bag of cocaine was found is a blind spot for surveillance cameras, according to a source familiar with the investigation. While there’s surveillance around where the bag was found, cameras are not trained directly on the West Wing cubbies near the lower-level entrance where it was discovered, the source said, making it difficult to identify who left the bag behind.

“We’ve been briefed by Secret Service on the outcome of their investigation and are reviewing the information,” White House principal deputy press secretary Olivia Dalton said in a statement.

CNN previously reported that cocaine was found in a cubby near the ground floor entrance to the West Wing where staff-led tours of the White House pass through on their way into the building.

Visitors entering the West Wing for tours are asked to leave their phones in those cubbies, which can also be used by staff who cannot bring their phones into a SCIF, or sensitive compartmented information facility, where classified materials are handled. The cubbies are located near the Situation Room, which has not been used for months due to ongoing renovations.

White House press secretary Karine Jean-Pierre expressed confidence last week that Secret Service will “get to the bottom” of the incident.

The discovery of a powdery substance by Secret Service personnel conducting routine rounds of the building had prompted a brief evacuation as part of what the Secret Service described as “precautionary closures.”

The Secret Service briefed the House Oversight and Accountability Committee on the case Thursday morning. Leaving that briefing, GOP Rep. Tim Burchett told CNN the case was “the most ridiculous thing I’ve ever seen in my life.”

He said that the bag contained less than a gram of cocaine.

“Y’all have all been to the White House. You give your Social Security number, you get, I mean, I’m sure they have facial identification and everything else, and to say that they don’t know who it is, to me, somebody should lose their job over this, a lot of people,” he said.

He added, “Somebody walks in the White House, the most secure building in the United States of America – in the world, actually – and can place something in a locker. What if it was a biological entity? What if it was something that had an emergent that would, you know, would mature over a few days and it could – you know, it’s just a lot of questions.”

GOP Rep. Marjorie Taylor Greene told reporters that the Secret Service informed members in their briefing that it had narrowed its list of suspects down to 500 people. Greene, who said part of the briefing was classified, said she asked Secret Service if they would drug test those individuals and she said their answer was no.

The list includes a mixture of staffers and others on a tour, according to GOP Rep. Lauren Boebert, but the Secret Service would not provide specifics.

Boebert said the cocaine was found in locker number 50 and the key to that locker is missing. A number of members raised issues with the locker system and how it needs to be more secure.

Republican Rep. Nancy Mace said the Secret Service had to get visitor logs and other information from the Biden administration through the Presidential Records Act because the locker where the cocaine was found is under the jurisdiction of the Biden administration.

This story has been updated with additional information.