(CNN) - With the sentencing to prison Wednesday of a Auschwitz functionary, a man in his 90s, one might expect that the prosecution of alleged Nazi criminals is drawing to a close.

World War II ended 70 years ago. Most of those involved in the Nazi death machine are dead or will die before long. Perhaps Oskar Groening, the "bookkeeper of Auschwitz," will be the last Nazi ever to stand trial.

On the contrary, says the chief Nazi hunter for the Simon Wiesenthal Center.

Groening's conviction set a precedent that has opened the door to further trials of alleged Nazi criminals, Efraim Zuroff told CNN by phone.

"At least several additional trials" can be expected, Zuroff said.

Formal complaint to be filed against Danish SS volunteer

The Wiesenthal Center issues a list every year of the most-wanted Nazis. The 2015 list had 10 names on it, as usual. One of those names was Groening's, and the work goes on.

Zuroff told CNN that he would file a formal complaint next week against a Danish citizen for crimes allegedly committed in Belarus.

The target of the complaint was a Danish SS volunteer, Zuroff said.

His description matches that of a person who is named on the most wanted list only as "X" -- a resident of Denmark who is wanted, according to the Wiesenthal Center, for "murder of Jews in Bobruisk," a city 90 miles southeast of Minsk, the capital of Belarus.

Others on the list live in Germany, Canada, and Norway.

The legal doctrine under which Nazis can be tried in Germany began to change with the conviction in 2011 of John Demjanjuk as an accessory to the murder of 28,000 Jews in the Sobibor death camp in Poland.

Prior to that trial, Zuroff said, prosecutors had to prove that a specific crime had been committed against a specific victim.

But simply proving that Demjanjuk had been a guard at the camp became enough for a conviction.

Groening case further broadens standard of proof

Now, Zuroff said, Groening's conviction has extended that doctrine still further. While Demjanjuk, as a guard, dealt with prisoners and moved them around, Groening had a desk job. He was, he once said, a mere "cog in the gears."

But that was enough to convict him of being an accessory to the murder of 300,000 people in the Auschwitz death camp in Nazi-occupied Poland, and to earn him a four-year prison sentence.

Interactive map: Nazi concentration camps

And that standard of proof will make new prosecutions more feasible, Zuroff said.

Asked whether, with most of the alleged criminals remaining now in their 90s, it is reasonable to expect more prosecutions, Zuroff reacted with vigor.

The standard is not the age of the accused, he said, but whether that person is physically and mentally able to stand trial.

"It's quite realistic," he said.

edition.cnn.com