After an avalanche of criticism at home and abroad, the German government announced late Monday it will establish a task force to investigate, “as quickly and as transparently as possible,” the provenance of a cache of more than 1,400 artworks that are suspected of being traded or looted during the Nazis’ reign and that are now in the hands of authorities in Bavaria.

In a statement, the government said it planned immediately to post 25 works on the website www.lostart.de, the government-funded database for works missing since World War II. Others will be posted as their provenances are documented, it said.

According to prosecutors in the Bavarian city of Augsburg, who have so far been solely responsible for dealing with the works, some 380 are believed to have been legally taken from museums by the Nazis under the “degenerate art” law of 1938. The ownership histories of another 590 works must be examined to determine whether they were acquired from Jewish owners under duress.

The task force will consist of at least six provenance experts, as well as representatives from various ministries, the statement said.

The German foreign minister, Guido Westerwelle, had earlier expressed concern that reluctance to publicize the contents of this art find could damage the international “trust that we have built over many decades” after World War II.

The statement did not offer information about when and how looted paintings might actually be returned to former owners.

That is precisely what people like David Toren want to know.

Mr. Toren last remembers seeing Max Liebermann’s “Riders on the Beach,” already known to be among this 1,400-work hoard, on the wall of his great-uncle’s villa in Breslau, then part of Germany. Mr. Toren was 13 and the war that would soon engulf the continent was less than a year away.

Mr. Toren’s lawyers recognized the work when it was made public last week along with a handful of others from the $1.4 billion stash, which Bavarian officials confiscated from the Munich home of Cornelius Gurlitt in February 2012 as part of a tax investigation. Mr. Gurlitt’s father, Hildebrand Gurlitt, was one of four art dealers authorized by the Nazis to trade in art during the war.

Mr. Toren, 88, won’t be able to see the actual painting. He is blind. But he said that he is determined to recover the picture and other works that once belonged to his family. “I am going to make it my business to get those paintings back,” Mr. Toren said, referring to “Riders” and others he and his lawyers believe might be part of the trove.

Mr. Toren, who lives in New York, said he has a letter, dated December 1939, three months after World War II started, showing that government authorities in Breslau had inventoried the art collection — including “Riders on the Beach” — and other valuables like porcelain, pottery, rugs and furniture owned by David Friedmann, his great-uncle, a Jewish industrialist there. The letter mentions a number of Impressionist paintings, including works by Rousseau, Camille Pisarro and Liebermann, and noted that Mr. Friedmann had been warned not to dispose of any of the art.

Jörg Rosbach, Mr. Toren’s lawyer in Germany, said he was stunned last Tuesday to see on television the painting he had long sought on behalf of his client. He said he had twice tried to contact state prosecutors in the Bavarian town of Augsburg who have responsibility for the case and had also tried to reach the archive in Magdeburg, in eastern Germany, that contains the government catalogs of stolen or missing art seized under the Nazis, but received no response.

Mr. Toren said his great-uncle died peacefully at the age of 86 before the war swept through Breslau — now part of Poland and called Wroclaw — but said that his great-uncle’s daughter, Lotte, committed suicide after being detained by the Nazis. Mr. Friedmann had owned four estates totaling 10,000 acres, Mr. Toren said, in addition to the Breslau villa. Mr. Toren said he himself escaped to Sweden as part of a kindertransport, a rescue mission for children, before the war started. He made his way to Israel after the war and is now a retired lawyer living in Manhattan. His older brother, who has dementia, lives in London, he said.

Mr. Toren’s situation is similar to that of other survivors and heirs who had their family’s possessions confiscated or stolen by the Third Reich or its agents and who are now wondering what to do next. “I don’t know where to put the claim,” Mr. Toren said.