The man dubbed the “bookkeeper of Auschwitz” has died aged 96, three years after his conviction for crimes in the Nazi genocide of Europe’s Jews during World War II, German media reports.

Oskar Groening was sentenced to four years in prison in 2015 for his role as an accessory to the murder of 300,000 of the Auschwitz concentration camp’s roughly 1 million victims.

He died in hospital and had yet to begin his sentence, magazine Der Spiegel reports.

It reported Groening died on Friday but prison authorities are yet to receive a death certificate.

Groening earned the moniker the “Bookkeeper of Auschwitz” because he reportedly took part in counting money from prisoners kept at the concentration camp.

He admitted during his trial that he witnessed the mass murders that took place, but did not take part himself.

He said he was morally guilty for the work he carried out at Auschwitz, which included sending bank notes he found in Jews’ luggage to SS offices in Berlin, where they helped to fund the Nazi war effort.

“It’s very clear that I am morally guilty for the murders and I acknowledge that guilt here today with remorse,” he said at his trial.

“As to the question of guilt under criminal law, this is for the court to decide.”

In 2005, Groening gave interviews about his work in the concentration camp in an attempt to persuade Holocaust deniers the genocide had taken place.

Groening’s court case was seen as one of the last major trials related to the Holocaust.

-with agencies