The British intelligence agency MI6 has distanced itself from the new head of the service, Blaise Metreveli, after revelations that her grandfather was a Nazi spy known as “The Butcher.”

Newspapers reported on Friday that her grandfather was Konstantin Dobrovolsky, who defected from the Soviet Red Army to become the chief informant for the Nazis in Chernihiv, Ukraine.

The Foreign Office, speaking on behalf of MI6, stated that Metreveli “neither knew nor met her paternal grandfather.”

A spokesperson added that her heritage “is marked by conflict and separation and, as is the case for many with Eastern European ancestry, is only partially understood.”

The Daily Mail, which first uncovered the family history of the new chief, reported finding hundreds of pages of documents in an archive in Freiburg, Germany. These revealed that Dobrovolsky was known by Wehrmacht commanders as “The Butcher” or “Agent No. 30.”

He reportedly signed letters to his Nazi superiors with “Heil Hitler” and claimed to have “personally taken part in the extermination of Jews.”

Documents indicate that Dobrovolsky looted the corpses of Holocaust victims, took part in the murder of Jews in the region, and laughed while watching sexual assaults on female prisoners.

After the war, Dobrovolsky’s wife Barbara and their two-month-old son fled to Britain. In 1947, she married David Metreveli, and her son took his stepfather’s surname. According to the Mail, some official documents still list his surname as Dobrovolsky.

Dobrovolsky’s son went on to become a radiologist and a veteran of the British armed forces. His daughter, Blaise Metreveli, was born in 1977.

Metreveli is the first woman to lead MI6 in its 116-year history. She joined the agency in 1999 and currently heads its technology and innovation division. She will become MI6’s 18th chief when she replaces Sir Richard Moore later this year.