Last Updated Mar 11, 2015 8:18 PM EDT
WASHINGTON -- Another possible case of misconduct involving the Secret Service is under investigation, CBS News has learned.
Sources familiar with the investigation tell CBS News two senior Secret Service agents are being investigated for allegedly driving an agency vehicle while under the influence of alcohol.
The incident happened after 11 p.m. on Wednesday, March 4. At the same time, the Secret Service was investigating a suspicious package near the White House grounds which turned out to be harmless.
The agents were returning from a retirement party for outgoing Secret Service spokesman Ed Donovan when they allegedly drove through a line of yellow plastic security tape placed around the scene and hit a barrier.
One agent was identified as Mark Connolly, the second-in-command on President Obama's protective detail. The other is George Ogilvie, a senior supervisor in the Washington field office.
Both agents have been reassigned to desk jobs and stripped of management roles while the Department of Homeland Security's Office of Inspector General investigates, according to DHS.
The White House first learned of the matter earlier this week when new Secret Service Director Joe Clancy informed the president's senior advisers, the Secret Service said.
Clancy immediately recommended that an outside agency investigate. President Obama and Homeland Security Secretary Jeh Johnson endorsed that recommendation.
A source familiar with the investigation said the inspector general's office is empowered to investigate not only the conduct of the special agents but also the uniformed division supervisor.
That supervisor may have overruled the recommendation of junior officers to conduct field sobriety tests.
The incident is just the latest black eye for the Secret Service.
Clancy, who took over permanently last month, came out of retirement in October to lead the agency on an interim basis after former Secret Service Director Julia Pierson resigned in the wake of several high-profile security breaches.
On Sept. 19, a 42-year-old Texas man, Omar J. Gonzalez, was able to scale the White House fence, enter the unlocked front doors of the building, and run all the way into the East Room before he was apprehended by an off-duty Secret Service agent.
Three days earlier, an armed security contractor with a criminal record was allowed on an elevator with President Obama during a visit to the Centers for Disease Control and Prevention in Atlanta.
Later in September, the Washington Post reported the Secret Service took four days to realize a gunman had fired at and hit the White House in 2011, despite the fact that some agents on duty believed the building had sustained fire.
Pierson took over as the agency's chief in March 2013 after the retirement of former director Mark Sullivan, who struggled with a prostitution scandal among agents traveling with the president and a pair of gate-crashers at a state dinner. Prior to taking over, Pierson had served as the Secret Service Chief of Staff since 2008.
2015 CBS Interactive Inc. All Rights Reserved.