A West German newspaper said today that a Stuttgart merchant in Nazi paraphernalia wrote the bogus Hitler diaries and sold them to Stern magazine for nearly $4 million.

The daily Stuttgarter Nachrichten, quoting what it called "reliable informants," said Konrad Fischer, alias Konrad Kujau, complained to friends 15 months ago that he was compelled to write "day and night" and was totally exhausted by the ordeal.

Fischer, described as a designer and calligrapher with a zealous interest in Third Reich artifacts, also showed one informant a suitcase stuffed with nearly 3 million marks ($1.2 million), the newspaper reported in a story to be published Friday.

Gerd Heidemann, the 51-year-old Hamburg reporter who acquired the 62 volumes for Stern and now faces a lawsuit for fraud by his former employers, admitted this week that Fischer was the source for the fake diaries.

Known only as "Dr. Kujau" to most of his unsuspecting neighbors, Fischer shut down his small basement storehouse of Nazi mementos and vanished more than two weeks ago when Stern unveiled its "scoop" in a globe-shaking publicity blitz.

Klaus Ulrich Moeller, the Stuttgart reporter who tracked down Fischer's circle of contacts, said in an interview his informant had given evidence under oath to "a large and responsible" law firm that passed the affidavit along to the city prosecutor. Stuttgart authorities were not available to confirm the account because today, Ascension Thursday, is a public holiday.

When informed of the report, Heidemann told the popular daily Bild that "I do not believe at all" that Fischer acted as solitary forger. He said that Fischer would have to be some kind of "wonder boy" to accomplish the painstaking task of writing more than 60 volumes in two years.

Heidemann admitted that he delivered suitcases filled with cash to Fischer in several installments in return for two or three diary books at a time. The last volume, he added, was acquired by Stern in April, just prior to the magazine's revelation.

The sacked journalist, who has been caught in repeated contradictions when describing his role in the diary hoax, recanted today his previous assertion that he did not enrich himself through the acquisition of the dairies.

Stern's "publisher paid me 25,000 marks about $10,000 for each delivery, which added up to 1.5 million marks $600,000 . It was to be declared as an interest-free loan which I would not have to repay," Heidemann told the Bild newspaper.

Fischer, whose shop was highly touted in the netherworld of collectors eager to buy Nazi artifacts, frequently told potential buyers that he gained access to his trove of Third Reich medals, flags and documents through high-ranking relatives who slipped the goods out of East Germany.

Past associates, including Nazi archivists and war historians, say that Fischer told them he came to the West as a refugee 20 years ago but still maintained close contacts with his powerful family members, alleged to include an army general and museum director.

Those two relatives, investigated by Stern after Heidemann provided a thorough account of his dealings with Fischer, turned out to be a railway station porter and a museum caretaker, according to Stern publisher Henri Nannen.

The Stuttgart report claims that Fischer used his design and writing skills to concoct the diaries in his villa in nearby Bissingen.

Fischer's female companion, Edith Lieblang, was quoted by the Stuttgart newspaper's informants as bemoaning the taxing work he had assumed in agreeing to write a book on Hitler for Stern.

Last week, the day after West Germany's federal archives announced that forensic tests proved the diaries were postwar forgeries, she reportedly told her employers that she intended to take a few days' leave of absence.

Since then, no trace of Fischer or her has been found.

In the wake of the fraud suit against Heidemann, the Hamburg prosecutor's office has opened a full investigation into Fischer's role in the case of the bogus diaries.