An 83-year-old woman who admitted she had served as a guard at a concentration camp during World War II was deported to Germany, federal officials said Tuesday.

Prosecutors would not say how they learned about Elfriede Rinkel, but a department spokeswoman said investigators routinely compare guard rosters and other Nazi documents to U.S. immigration records.

Rinkel admitted in court documents that she worked as a prison guard at the Ravensbrueck camp near Furstenberg from June 1944 until the camp was abandoned by the Nazi government in April 1945. According to the U.S. Department of Justice, she worked with an SS-trained attack dog but was not a member of the Nazi party.

"Concentration camp guards such as Elfriede Rinkel played a vital role in the Nazi regime's horrific mistreatment of innocent victims," said Alice Fisher, a Justice Department lawyer. "This case reflects the government's unwavering commitment to remove Nazi persecutors from this country."

As part of her June agreement with prosecutors, Rinkel gave up her green card, moved to Germany and agreed never to return to the U.S., according to the court documents. The government agreed to not release information about Rinkel's case, which began in April, until after her departure. She left this month.

A call to her lawyer Tuesday wasn't immediately returned.

Rinkel's husband, a German Jew whom she married after coming to the U.S., died in 2004. Her brother and sister-in-law, when reached at their Northern California home, said they were unaware of Rinkel's past and believed her husband had been, too. The couple asked not to be identified by name because they feared a backlash from friends and family.

More than 130,000 women passed through Ravensbrueck's gates between 1939 and 1945; an estimated 40,000 survived, according to the U.S. Holocaust Memorial Museum.

In January 1945, it had more than 45,000 prisoners, mostly women. The camp had more than 150 female guards and was a major training site for female concentration camp staff.

Rinkel was a furrier by trade in her hometown of Leipzig, according to her younger brother, who fought for the German army in North Africa and was captured by U.S. troops. In 1950, the general who ran the prison camp in Wyoming where he was held helped Rinkel's brother permanently settle in the U.S.

Nine years later, the brother and sister-in-law sponsored Rinkel to come to the Bay Area where she met her husband, Fred Rinkel, at a German-American friendship club, according to the couple.

Fred Rinkel received a Jewish burial in San Francisco and his wife was to be interred next to him, but she has since changed those plans.