A former National Archives employee on Tuesday admitted in federal court that he stole nearly 1,000 audio recordings and sold some on eBay.

Leslie C. Waffen, 66, who was chief of the Archives’ audiovisual holdings, pleaded guilty to embezzlement of government property. He is scheduled to be sentenced March 5 in federal court in Greenbelt.

Federal officials said Waffen sold items belonging to the Archives on eBay in September and October of last year. They said they found “documentary evidence” in Waffen’s home he had been selling items belonging to the Archives since at least August 2001.

Assistant U.S. Attorney Arun G. Rao said in court that one item sold by Waffen was an original master copy of a voice recording of Babe Ruth on a December 1937 hunting trip. The recording sold for $34.74, Rao said.

“This case is especially egregious because the defendant was a high-ranking government employee who violated his obligation to protect historical records that belong to the National Archives and Records Administration,” U.S. Attorney Rod J. Rosenstein said in a statement. “These items were entrusted to the National Archives to be used by all citizens, not to be auctioned for personal profit to the highest bidder.”

Authorities said a tipster led them to Waffen, who worked for the Archives for 37 years. Last October, weeks after Waffen retired from the agency, federal agents raided his Rockville home.

Rao said in court that agents seized 6,153 sound recordings from Waffen’s home, and that officials confirmed that 955 of them belonged to the National Archives.

Archivist of the United States David S. Ferriero said the agency has bolstered security in its facilities. For instance, guards now check the bags of everyone — including employees — leaving the D.C. and College Park facilities, a practice that will be expanded to all Archives’ facilities nationwide, authorities said.

“I am disappointed and angered by Mr. Waffen’s violation of the trust placed in him by colleagues and the American people to safeguard our nation’s history,” Ferriero said. “It is an outrage that an employee entrusted with protecting our heritage became a threat to those holdings.”

Rao said that during sentencing, the government will argue that the recordings Waffen took are valued at at least $70,000. Waffen’s defense attorney will ague the stolen recordings are worth between $30,000 and $70,000.

The audiovisual holdings contain more than 90,000 film, sound and video recordings made by the government and private sources. many are presidential recordings, kept at presidential libraries and museums. Others are held at the Archives’ facility in College Park.

A 2004 New York Times article described Waffen’s efforts to preserve the only known audio recording of John F. Kennedy’s Assassination.

This post has been updated.