State prosecutors in the town of Celle are investigating Karl Friedrich Berger, 94, over his alleged involvement in the murder of 70 prisoners at a satellite camp of Neuengamme network near Hamburg in 1945.

A trial in March found that Mr Berger, who lives in Tennessee, receives a state pension from Germany based on employment and “wartime service”.

US Department of Justice (DoJ) documents state he participated in “willing service as an armed guard of prisoners at a concentration camp where persecution took place”.

Mr Berger told The Washington Post he was ordered to work at the camp.

He added: “After 75 years this is ridiculous. I cannot believe it. I cannot understand how this can happen in a country like this. You’re forcing me out of my home.”

DoJ assistant attorney general Brian A Benczkowski said: “Berger was part of the SS machinery of oppression that kept concentration camp prisoners in atrocious conditions of confinement.

“This ruling shows the department’s continued commitment to obtaining a measure of justice, however late, for the victims of wartime Nazi persecution.”