A 90-year-old man convicted last year of killing three Dutch civilians while part of a Nazi SS hit squad has been taken to prison to begin a life sentence, the British Guardian reported on Thursday.

Heinrich Boere was taken by ambulance from the home for the elderly where he lived to an unspecified detention facility, a spokesman for prosecutors told the Guardian.

The spokesman said that a court-appointed expert’s report had ruled that Boere was fit to serve his term, despite his age, adding that a “suitable” facility had been found.

Boere was born in Germany to a Dutch father and a German mother but grew up in the Dutch town of Maastricht. He joined the Waffen SS when the Nazis overran his hometown in 1940.

He escaped from a prisoner of war camp in the Netherlands in 1947 and returned to Germany.

A tribunal in Amsterdam sentenced him to death for the killings in his absence in 1949 but the sentence was later commuted to life in prison.

In April 2008, more than 60 years after the killings, Boere was indicted in Germany. A court in Aachen sentenced him to life in prison in March 2010 after he confessed to the killings.

The BBC reported that the three men Boere admitted to have killed were Fritz Bicknese, a chemist and father of 12; Frans Kusters, a Dutch resistance member who owned a bicycle shop; and Teun de Groot, who helped Jews go into hiding.

The report noted that Boere argued that he risked being sent to a concentration camp if he refused to carry out the shootings.

“At no time in 1944 did I act with the feeling that I was committing a crime,” he was quoted as having told the court during his trial, but added that 65 years later he saw things from a different perspective.

A federal court later rejected his appeal.

In 2008, Boere was placed on the Simon Wiesenthal Center’s list of most wanted Nazi criminals.