A former Nazi concentration camp guard who lived in the US for more than 60 years returned to Germany on Saturday after being expelled, a police spokesman said.
The 95-year-old man faces questioning by police after arriving at Frankfurt airport. He was not arrested.
US Justice Department officials named him as Friedrich Karl Berger, while Germany authorities refer to him only as Friedrich Karl B.
A US court last year ruled that he should be expelled after prosecutors in the northern German town of Celle opened an investigation into whether he was involved in the murder of prisoners at a satellite concentration camp of the Neuengamme network near Hamburg in 1945.
According to German prosecutors Mr Berger, who lived in the US since 1959, admitted to guarding prisoners for a few weeks in the Meppen area close to the Dutch border without witnessing any killings or abuse of prisoners.
The German case against him was dropped in December after prosecutors were unable to dispute his account.
The US court found that prisoners at the camp were held in atrocious conditions and were exploited for outdoor forced labour, working "to the point of exhaustion and death", the US Department of Justice said.
The court also found, and Mr Berger admitted, that he guarded prisoners to prevent them from escaping during their dawn-to-dusk workday, on their way to worksites and on their way back to the camp in the evening.
A spokesman for the prosecutor's office in Celle said police in the German state of Hesse had been asked to question him on his return to Germany. A police spokesman said there was no live investigation linked to him and he is was not been taken in custody.
The Department of Justice said it marshalled evidence leading to Mr Berger's removal that its human rights section found in the US and in Europe, including records of the trial in Nuremberg 75 years ago of former leaders of the Nazi regime.
In recent years, prosecutors brought charges against several former Nazis, seizing the last opportunity to secure justice for the millions who died in concentration camps.
This month, prosecutors charged a 100-year-old German man with being an accessory to 3,518 murders committed while he was allegedly a guard at the Sachsenhausen concentration camp.