Several hundred German investors are complaining through their diplomatic spokesmen in the United States that they have been swindled in a classic American desert land fraud.

The target of their ire is 61-year-old Las Vegas entrepreneur Leonard Rosen, whom they charge enticed them into buying shares in an investment fund that eventually paid them back in overpriced Nevada desert land, resulting in some cases, in loss of life savings.

Rosen, a familiar figure in this mecca of chance, has attracted the attention of authorities in other land ventures to which he has applied himself. One was his association with GAC, a Florida land sales company that was forced to return millions of dollars to investors who discovered that their holdings were under water.

Rosen is scheduled to stand trial in Las Vegas this week on charges that he didn't report $5.5 million in income from land sales in Las Vegas. That indictment stems from a civil audit of the Rosen-funded firm, Preferred Equities.

The case of the disgruntled Germans springs from a scheme they say is reminiscent of the operations of financial tycoon Bernard Cornfeld, founder of the ill-fated Investors Overseas Services. Some of Cornfeld's former mutual fund sales employees have wound up working for Rosen, according to U.S. authorities who investigated his case in Germany.

The story begins in March, 1970, when Rosen lectured in Munich, to audiences of prospective German investors.

Rosen passed out glossy brochures with photographs of prominent Americans and lush green valleys in the United States. "At last," read the brochure, "there's a place in Nevada where YOU CAN'T LOSE!"

Scattered around the cover are the names of some of the bigger gambling casinos in town: Circus Circus, Caesars Palace, etc.

The brochure described CalVada Valley, located in the desert more than an hour's drive west of Las Vegas, as "the open door to uncluttered wilderness parks, unbelievable natural beauty." It also said the valley was "on the fringe of the fastest-growing metropolitan area in the United States."

But Rosen, who identified himself as president of Investment Management Crop. of America, S.A. (IMCA), a Panamanian-based firm, wasn't selling the land itself. He was selling shares in an investment fund called Parfund.

According to Timm Beckmann, a German insurance broker at that meeting who eventually invested $25,000 in Parfund and $4,000 in IMCA debentures, Rosen claimed that Parfund would be investing in CalVada land. In fact, according to Beckmann, Rosen indicated to the Germans that his own son, Ronnie, was head of Preferred Properties, a firm involved in the Nevada land venture.

Beckman's statements are part of a large package he sent to Nevada consumer affairs division offices to protest what eventually happened to his investment.

Beckman said that in November, 1970, the West German Securities Control Agency refused to sanction the sale of Parfund shares, in Germany.

After many Germans attempted to contact Rosen, he came back to the investors in June, 1971, with a proposal.

He offered than $11 of CalVada land for every $10 of Parfund shares.

Beckmann said he took the deal "to save my investment," and exchanged $25,000 in Parfund shares for five lots in CalVada. He received the deeds between July, 1971, and October, 1974.

Meanwhile, IMCA also defaulted on interest: payments from the debentures, and by early 1972, Beckmann said, he realized that the $4,000 investment was lost.

But as a result of the Parfund transactions, Beckmann began receiving tax bills from the Nye County. Nevada, tax assessor, who valued his land at $15,000 - a price German authorities said was artificially pumped up.

They contend that Rosen, using a series of dummy domestic and off-shore corporations that he controlled, sold the land to himself before trading it to them, boosting the sale price and consequently placing and inflated value on the land.

Whether or not those dummy transactions took place, one thing is apparent: the assessed value of the property was influenced by the retail price of the land set by preferred Equities when it sold the land set by preferred Equities when it sold the land to Parfund. Preferred Equities was founded by Rosen, and Parfund was run by him, according to federal investigators.

Heinz Pallasch, a deputy consul for the West German government in San Francisco, says the high taxes charged the Germans were unfair because Preferred Equities was paying much less on the same amount of property it still owned in the development.

Pallasch went to Nye County to try to pursuade tax authorities there that many of the Germans had invested their life savings in Parfund, and now the land in Calvada, and they could not afford the tax payments.

Beckmann said he was being assessed $500 a year on his property.

But Pallesch could be of little help. According to Nye County treasurer Rena Bailey, all subdivided lots are taxed at a higher rate than lots not yet subdivided or sold. Nye County deputy assessor Terry Sotak agreed, adding that unsold land is assessed at about one-eighth of the value of sold land.

Last October the Nye County tax assessor put up the auction more than 100 lots owned by 85 Germans who could not, or would not, pay their taxes.

The lots, which the assessor had valued at $5,000 for purposes of taxing ferred Equities for less than $800 each.

"Aside from the probability of my the Germans, were sold back to Pre-having been the victim of a major land fraud. I am, of course, curious why I am being asked to pay high taxes on property which apparently is of little value," said Beckman in his letter, sent before the tax auction as part of the package that went to the state consumer affairs offices.

"As you can imagine," he continued, "I have invested my life's savings in these enterprises, and it is difficult to face my retirement years without any of the funds that I have worked for all my life."

According to deputy assessor Sotak, about 100 residences, mostly mobile homes, now make up the entire live-in portion of Calvada.

Sotak said his office cut the assessed value of the Calvada land in half last year "because we had originally assessed the land much too high."

He said that in 1970, when the land was first assessed, it was assumed that a development would sprout up rapidly in the once prosperous agricultural oasis.

Meanwhile, Preferred Equities keeps on selling, although the firm has has problems with Nevada authorities for the past few years. In 1974 it was cited, with several of its salesmen, for allegedly engaging in the use of "false" misleading and deceptive" sales practices.

But the charges were dropped following negotiations between state Real Estate Division officials and the firm's executives.

Although neither Rosen nor Preferred Equities president Jack Soules responded telephone calls from The Washington Post. Soules recently told an interviewer for the local Valley Times that neither of them had done anything wrong.

Soules said that Beckmann was using his complaint to "blackmail" the firm into refunding his investment.

Soules said Parfund was a legitimate investment fund for land development, and the West German government halted the company's activities in Germany because of scandals uncovered in other international investment funds not related to Parfund.

The exchange of CalVada land for Parfund shares was a good-faith attempt by Rosen to protect the share-holders' investment, Soules said.

Soules further speculated that the Germans were not paying their taxes because they failed to recognize the potential value of the property.

He said that Preferred's asking price for unsold lots in CalVada has increased more than 40 per cent over the past five years.

In House and Home Magazines's April, 1969, issue, Roen and his brother Julius were described as th top two land salesmen in the U.S.

According to that article, the brothers together amasses $128 million after selling GAC Corp., a holding company with huge Florida land sales.

The Rosens had founded Gulf American, a Florida-based firm that grew into their 1969 holdings, with only $125.000 a dozen years earlier.

In 1974, the Federal Trade Commission ordered GAC to refund $2.8 million to buyers who purchased substantial parcels of land that turned out to be under water.