A German federal court has rejected a former Auschwitz death camp guard’s appeal against his conviction for being an accessory to murder, a decision greeted Monday as setting an important precedent for future prosecutions of Holocaust perpetrators.

Oskar Groening, now 95, was convicted in July 2015 of being an accessory to the murder of 300,000 Jews and sentenced by a court in Lueneburg to four years in prison. Judges found that he knew Jews were being slaughtered and supported the killings through his actions.

The Federal Court of Justice’s decision to uphold the former SS sergeant’s conviction boosts ongoing cases against other suspects and raises the possibility of further investigations against others who served at Nazi death camps or in other functions.

“It’s very exciting news,” said Efraim Zuroff, the head Nazi hunter at the Simon Wiesenthal Center in Jerusalem. “The door is open.”

Groening testified at his trial that he oversaw the collection of prisoners’ belongings and ensured valuables and cash were separated to be sent to Berlin. He said he witnessed individual atrocities, but did not acknowledge participating in any crimes.

Presiding Judge Franz Kompisch ruled last year, however, that Groening was part of the “machinery of death,” helping the camp function and also collecting money stolen from the victims to help the Nazi cause, and could thus be convicted of accessory to the murders committed there.

In throwing out Groening’s appeal, the federal court noted that his responsibilities had included keeping watch on the inmates and preventing resistance or attempts to flee by force.

It also rejected appeals from several survivors and their relatives who had joined the trial as co-plaintiffs, as is allowed under German law, and had sought a tougher conviction.

It is the first time an appeals court has ruled on a conviction obtained under the logic that simply having served at a death camp, and thus helping it operate, is enough to convict someone as an accessory to the murders committed there — even if there was no evidence of involvement in a specific killing.

In a joint statement, three attorneys who represented 50 Holocaust survivors and families as co-plaintiffs at the Groening trial welcomed the verdict, saying that it came “late, but not too late.”

“We and our clients believe that every member of the SS who was involved in the systematic murder of the Jews in the extermination and concentration camps of the SS committed accessory to murder,” they said.

In 2011, former Ohio autoworker John Demjanjuk became the first person convicted in Germany solely for serving as a death camp guard without evidence of being involved in a specific killing. Demjanjuk, who always denied serving at the Sobibor camp, died before his appeal could be heard.

Groening has remained free pending the outcome of his appeal. His lawyer, Hans Holtermann, said he expects that prosecutors will now examine whether he is in good enough health to be taken into custody.

Holtermann said he will consider whether to take the case to Germany’s highest court, the Federal Constitutional Court.

He noted that the appeal ruling didn’t address concerns about how long it took to bring Groening to trial. Groening was previously investigated in the 1970s but authorities then shelved the case.

(AP)