Heinrich Boere, who murdered Dutch civilians as part of a Nazi Waffen SS hit squad during World War II but avoided justice for six decades, died Dec. 1 in a prison hospital while serving a life sentence. He was 92.

Mr. Boere died in the facility in Froendenberg, Germany, where he was being treated for dementia, North Rhine-Westphalia Justice Ministry spokesman Detlef Feige said. He had been the state’s oldest prisoner.

Mr. Boere was on the Simon Wiesenthal Center’s list of most-wanted Nazi war criminals until his arrest in Germany and conviction in 2010 on three counts of murder.

“Late justice often sends a very powerful message regarding the importance of Nazi and Holocaust crimes,” the center’s top Nazi hunter, Efraim Zuroff, said in a telephone interview from Jerusalem. “It’s a comforting thought to know that Boere ended his life in a prison hospital rather than as a free man.”

During his six-month trial in Aachen, Mr. Boere admitted killing three civilians as a member of the “Silbertanne,” or “Silver Fir,” hit squad, a unit of largely Dutch SS volunteers responsible for reprisal killings of compatriots who were considered anti-Nazi.

Heinrich Boere, who died Dec. 1 in a German prison hospital, was on the Simon Wiesenthal Center’s list of most-wanted Nazi war criminals until his arrest and conviction in 2010 on three counts of murder. (Martin Meissner/AP)

He sat through the proceedings in a wheelchair and was regularly monitored by a doctor. He spoke little but told the court in a written statement that he had no choice but to obey orders to carry out the killings.

“As a simple soldier, I learned to carry out orders,” Mr. Boere testified. “And I knew that if I didn’t carry out my orders I would be breaking my oath and would be shot myself.”

But the presiding judge said there was no evidence that Mr. Boere ever tried to question his orders. The judge characterized the killings as hit-style slayings, with Mr. Boere and his accomplices wearing civilian clothes and surprising their victims at their homes or places of work late at night or early in the morning.

“These were murders that could hardly be outdone in terms of base­ness and cowardice beyond the respectability of any soldier,” the judge said in his ruling. “The victims had no real chance.”

Mr. Boere remained unapologetic to the end for his actions, saying that he had been proud to volunteer for the SS and that times were different then.

Heinrich Boere was born to a Dutch father and German mother in Eschweiler, Germany, on the outskirts of Aachen. He moved to the Netherlands when he was an infant.

In testimony during his trial, Mr. Boere said he remembered his mother waking him the night Germany invaded the Netherlands in 1940 and seeing Stuka dive bombers overhead. Instead of fearing the German bombs, he said, his family was elated as the attack unfolded.

“[My mother] said, ‘They’re coming; now things will be better,’ ” he told the court, before later adding: “It was better.”

After the Germans had overrun his hometown of Maastricht and the rest of the Netherlands, he saw a recruiting poster for the Waffen SS, signed by Heinrich Himmler. It offered German citizenship after two years of service and the possibility of becoming a policeman after that.

The 18-year-old showed up with 100 other Dutchmen at the recruitment office and was one of 15 chosen.

“I was very proud,” he told the court.

After fighting on the Russian front, he ended up back in occupied Holland as part of the “Silbertanne” hit squad.

According to statements he made to Dutch authorities after the war, he and a fellow SS man were given a list of names slated for “retaliatory measures.”

He killed pharmacist Fritz Hubert Ernst Bicknese with a pistol in his pharmacy and then he and the accomplice killed Teun de Groot when the bicycle-shop owner answered the doorbell at his home.

They forced the third victim, Franz Wilhelm Kusters, into their car, drove him to another town, stopped on the pretense of having a flat tire and shot him.

Mr. Boere managed to escape the prisoner-of-war camp where he was being held in the Netherlands in 1947 and eventually return to Germany.

In 1949, a Dutch court sentenced him to death in absentia — the sentence was later commuted to life imprisonment — but the case seemed to fall through the cracks. In 1980, the Netherlands sought Mr. Boere’s extradition, but a German court refused in 1983 on the grounds that he might have German citizenship; at the time, Germany had no provision to extradite its own nationals.

A state court in Aachen ruled in 2007 that Mr. Boere could legally serve his Dutch sentence in Germany, but an appeals court in Cologne overturned the ruling, calling the 1949 conviction invalid because Mr. Boere was not there to present a defense.

In 2008, a prosecutor in Dortmund reopened the case and charged Mr. Boere with the three murders.

During his trial, Mr. Boere told the court that he was aware of the possibility that he would be pursued by authorities, so much so that he never married.

“I always had to consider that my past might catch up with me,” he said. “I didn’t want to inflict that upon a woman.”

— Associated Press