A 92-year-old former member of an Einsatzkommando group has had the revocation of his Canadian passport overturned – for the third time.

Helmut Oberlander served with Ek 10a, part of Einsatzgruppe D, which killed over 20,000 civilians, the majority of whom were Jews. An ethnic German born in the Ukraine, he was conscripted into the force, where he acted as an interpreter, listening in to Russian radio transmissions. There is no evidence that he killed anyone himself.

Mr Oberlander moved to Canada in the 1950s, and became a Canadian citizen in 1960, without divulging his wartime record.

Since 1995, Jewish groups such as the Centre for Israel and Jewish Affairs have attempted to get Mr Oberlander’s citizenship revoked and the man deported, on the grounds that he "lied about his complicity in these atrocities and gained Canadian citizenship fraudulently".

Mr Oberlander has been stripped of his citizenship three times, only to have it returned to him each time on appeal. He has always maintained that he was not a part of the Ek 10a force by choice, and that he would have been killed had he not complied.

In its latest judgment, the Canadian Supreme Court ruled that the Canadian government could not deport Mr Oberlander unless it could categorically prove he was a willing member of Ek 10a.