Prosecutors have reopened hundreds of dormant investigations of former Nazi death camp guards and others who might now be charged under a new precedent set by the conviction of retired U.S. autoworker John Demjanjuk, The Associated Press has learned.

Given the advanced age of all of the suspects -- the youngest are in their 80s -- the head of the German prosecutors' office dedicated to investigating Nazi war crimes told the AP that authorities are not even waiting until the Demjanjuk appeals process is over.

"We don't want to wait too long, so we've already begun our investigations," prosecutor Kurt Schrimm said.

Meantime, the Simon Wiesenthal Center's top Nazi-hunter, Efraim Zuroff, told the AP he would launch a new campaign in the next two months -- a successor to his Operation Last Chance -- to track down the remaining Nazi war criminals.

He said the Demjanjuk conviction has opened the door to prosecutions that he had never thought possible in the past.

"It could be a very interesting final chapter," he said by telephone from Jerusalem. "This has tremendous implications even at this late date."

Demjanjuk, now 91, was deported from the U.S. to Germany in 2009 to stand trial. He was convicted in May of 28,060 counts of accessory to murder for serving as a guard at the Sobibor death camp in Nazi-occupied Poland.

It was the first time prosecutors were able to convict someone in a Nazi-era case without direct evidence that the suspect participated in a specific killing.

In bringing Demjanjuk to trial, Munich prosecutors argued that if they could prove that he was a guard at a camp like Sobibor -- established for the sole purpose of extermination -- it was enough to convict him of accessory to murder as part of the Nazi's machinery of destruction.

After 18 months of testimony, a Munich court agreed and found Demjanjuk guilty, sentencing him to five years in prison. Demjanjuk, who denies ever having served as a guard, is currently free and living in southern Germany as he waits for his appeal to be heard.

Schrimm said his office is now again going over all of its files to see if others may fit into the same category as Demjanjuk.

He could not give an exact figure, but said there were probably "under 1,000" possible suspects who could still be alive and prosecuted, living both in Germany and abroad. He would not give any names.

"We have to check everything -- from the people who we were aware of in camps like Sobibor ... or also in the Einsatzgruppen," he said, referring to the death squads responsible for mass killings, particularly early in the war before the death camps were established.

It has not yet been tested in court whether the Demjanjuk precedent could be extended to guards of Nazi camps where thousands died but whose sole purpose was not necessarily murder.

Murder and related offenses are the only charges that aren't subject to a statute of limitations in Germany.

Even the narrowest scenario -- looking at the guards of the four death camps used only for killings: Belzec, Sobibor, Chelmno and Treblinka -- plus those involved in the Einsatzgruppen could lead to scores more prosecutions, Zuroff said.

"We're talking about an estimated 4,000 people, to round it off," he said. "Even if only 2 percent of those people are alive, we're talking 80 people -- and let's assume half of them are not medically fit to be brought to justice -- that leaves us with 40 people, so there is incredible potential."

Immediately after the war, top Nazis such as Hermann Goering were convicted at war-crimes trials run by the Allied powers, while investigations of the lower ranks eventually fell to German courts.

But there was little political will to aggressively pursue the prosecutions, and many of the trials ended with short sentences, or acquittal, of suspects in greater positions of responsibility than Demjanjuk allegedly had.

For example, Karl Streibel -- the commandant of the SS camp Trawniki where Demjanjuk allegedly was trained -- was tried in Hamburg but acquitted in 1976 after the judges ruled it hadn't been proven that he knew what the guards being trained would be used for.

But the current generation of prosecutors and judges in Germany has shown a new willingness to pursue even the lower ranks, something applauded by Zuroff.

"Our goal is to bring as many people to justice as possible," Zuroff said. "They shouldn't be let off if they're less than Mengele, less than Himmler ... in a tragedy of this scope their escaping justice should not in any way mean that people of a lesser level would be ignored."

Working in favor of the new investigators is the fact that most suspects would likely have lived openly under their own names for decades, thinking they had no prosecutions to fear.

Those who are harder to locate will be the focus of the Wiesenthal center's new appeal, which Zuroff said would include unspecified reward money for information that helps uncover a suspect.

On the other hand, Schrimm said it only makes sense to try to bring new cases to trial once the Demjanjuk case is through the appeals process, rather than expend all the resources needed to charge a suspect only to have the case thrown out if Demjanjuk wins. But the appeal could still take at least another six months to a year -- or longer -- and the suspects are not getting any younger.

"It's very clear that they're old, that's why we're preparing everything now so that as soon as there is a final decision, we can move immediately with charges," Schrimm said.

Zuroff said he hoped that the appeal could somehow be fast-tracked so that new charges could be filed before it is too late.

"This ... is a test for the German judicial system to see if they can expedite this in an appropriate manner to enable these cases to go forward," he said.