BERLIN (AP) — Hannover prosecutors have reopened an investigation in which a 95-year-old former SS officer is accused of being involved in two 1943 massacres of Jews in the Polish city of Lublin.

The prosecutors' office made the decision based on a letter that suspect Erich Steidtmann wrote in October 1943. Steidtmann was a captain in the Nazi's elite force, the SS, and also the head of a company belonging to the infamous Hamburg Polizeibataillon 101.

"We reopened the investigations to check whether he was on vacation during the time of the massacres or whether he was at the location when it happened," prosecutor Kathrin Soefker told The Associated Press on Thursday.

The prosecutor said a new understanding of an abbreviation in the letter could indicate that Steidtmann was not on home leave when the shootings of thousands of Jews took place, as he had told prosecutors during earlier investigations in the 1960s.

The abbreviation in question was a military code to indicate that the sender of the letter was in the field. The letter itself was dated October 31, 1943 — three days before the massacres began.

During the so-called "Mission Harvest Festival" massacres on November 3 and 4, 1943, tens of thousands of Jews in the district of Lublin were shot by Nazi officers, among them members from Steidtmann's Hamburg Polizeibataillon 101 company.

Soefker said her office was searching archives and contacting witnesses for further proof that Steidtmann was in Lublin when the shootings took place.

"We have contacted the federal archives in Berlin to find out if they still have a record of when exactly Steidtmann was on home leave," Soefker said.

The prosecutor's office also ordered a renewed interrogation of Steidtmann himself, who lives in Hannover.

Steidtmann's involvement in Nazi crimes has been investigated several times in the past, including his alleged involvement in killings at the Warsaw Ghetto in 1943, but there has never been sufficient proof to convict him of any crimes.

The new evidence was discovered by two journalists from daily Sueddeutsche Zeitung and a German historian who works for the Simon Wiesenthal Center.

"We're very proud and pleased that we played a role in the reopening of this case," Efraim Zuroff, the top Nazi hunter at the Simon Wiesenthal Center said from Jerusalem. "Steidtmann is certainly of equivalent notoriety as some of the people on our list of the top most wanted Nazis."