The Swiss bank account of a mysterious Brussels firm received $153,000 in unauthorized "commission" on Continental Grain Corp. sales to Jamaica during a six-month period in 1977, according to documents made available to The Washington Post.

The documents, which also were supplied to the U.S. and Jamaican governments, triggered an investigation that led to the firing last week of Dexter Rose, head of the socialist government's importing agency, the State Trading Corp.

The Jamaican investigation is focusing on allegations that Rose and an aide were involved in an elaborate international scheme to collect kickbacks from Continental and launder the money through Agrocom International Ltd. in Brussels and its Swiss bank accounts.

The Jamaican documents and an investigation by The Washington Post open a new chapter in the story of "questionable payments" by U.S. multinational corporations. They also provide a rare glimpse of the international grain trade, which is dominated by privately owned firms like Continental, which are beyond the usual scrutiny of government regulators.

A Jamaican cabinet minister announced Friday in broadening its investigation of whether kickbacks were paid by firms supplying the issland nation with $150 million to $200 million a year in imports.

He said a warrant had been issued for the arrest of Rose, the career government official who headed Jamaica's import agency until he disappeared a few days ago.

Before Rose "eluded surveillance" and fled Kingston last Monday, he admitted having a bank account outside the country in violation of Jamaica's strict currency controls, embassy officials here said. Rose also told investigators he woned a Liberian corporation called Young & Willcox, whose address is a garage in Brussels, Belgium.

Rose, a former World Bank official, left Jamaica last Monday for Miami, only hours before the cabinet of Prime Minister Michael Manley met to fire him, the officials said.

Also dismissed was Sedley K. Pyne, head of the Washington office of Jamaica Nutrition Holdings Ltd., the country's grain-buying agency.

Neither Pyne nor Ross could be reached for comment.

The Jamaicans said they are trying to determine whether the Continental "commissions" ended up in what appear to be two Liberian shell corporations, Rose's Young & Wilcox and Structural Redevelopment Corp., which the documents allege was owned by Pyne.

Jamaican embassy officials said they were "not aware of any commissions" being paid on the nation's grain purchases. "We see no need for commissions," one said.

Jamaica Nutrition Holdings Ltd. was set up in 1974 as a state-owned monopoly to deal directly with grain companies and avoid paying middlemen commissions, the embassy officials said.

Richard Carter, the Continental vice president who handled the sales to Jamaica, asknowledged that commissions were paid to Agrocom's Swiss accounts. But he said, "As far as we were concerned it was a perfectly above-board type transaction." He refused to say what Agrocom had done to earn a commission on the Jamaican sales in 1977.

The documents show that Continen-

Nor have they yet found anything about Structural Redevelopments Corp., another Liberian company formed with bearer shares in January 1977.

Agrocom, the Belgian firm whose Swiss accounts collected the American commissions on Jamaican sales, also leaves a cold trail in Brussels. European grain traders said they never heard of it. [TEXT OMITTED ON SOURCE] tal paid Agrocom commissions of $153,000 on nearly $12 million worth of corn and wheat sales to Jamaica in the first six months of 1977.

U.S. Department of Agriculture and grain trade experts agreed with the Jamaicans that there was no need for the commissions to be added to the price the Caribbean nation paid for the grain.

Jamaican investigators said they have no evidence that Continental knew the commissions were unauthorized. Continental's Carter said, "It is our policy not to pay commissions to government officials."

Jamaica paid cash for the grain, purchased from Continental in the firs six months of 1977, the period covered by the documents. Since that time it has purchased increasingly larger amounts of grain on long-term, low-interest Food for Peace loans financed by U.S. taxpayers.

The shift toward U.S. subsidized grain purchases followed a change in policy toward Manley's socialist government when the Carter administration came to power.

Previous U.S. policy toward Jamaica had been colored by concerns about Manley's close ties to Cuban Premier Fidel Castro and the Jamaican's avowed support for such Castro adventures as sending troops to Angola.

In early 1977, however, Rosalynn Carter and U.N. Ambassador Andrew Young visited Jamaica and made promises of increased U.S. aid.

Commission payments on Food for Peace shipments are prohibited by law. Continental's Carter emphatically denied that any commissions were paid on these so-called PL-480 shipments.

Agriculture Department investigators said they have found no sign of illegal commissions on Food for Peace sales to Jamaica in the transactions covered by the document.

The increased use of deferred-payment Food for Peace grain purchases -- from $1.5 million in 1975 to about $10 million a year now -- has helped the Jamaican economy. The Manley government had been forced to impose stringent fiscal controls to meet terms of a $244 million International Monetary Fund Ioan designed to ease its foreign exchange deficits.

The firing of Rose and Pyne amid charges of skimming money from much-needed foor programs has touched off a political furor in Jamaica.

Newspaper editorials and opposition party leaders have questioned why Rose was allowed to slip out of the country. They also demanded a parliamentary investigation of the allegations.

And even government officials have acknowledged the ironic possibility that capitalist-style white-collar criminals may have looted the socialist nation's beggest government-owned enterprise.

Jamaica Nutrition Holdings was formed in 1974 to take over the grain importing business from a group of American firms, in hopes of reducing prices and assuring steady supplies.

"Econommies have been made, though perhaps not as many as we though," one Jamaican official said wryly, in reference to the alleged kickbaks to salaried government officials.

A Washington office for Jamaica Nutrition was set up in 1975. Herbert Waters, a former State Department official now in the grain trade, was hired to train Pyne to run the operation.

In August 1975, according to Liberian government records, Rose organized young & Wilcox Corp. through Washington attorney H. George Schweitzer.

Schweitzer said in an interview last week that he has had no further dealings with the company.

Rose's firm was set using "bearer shares," which do not identify the owners of the stock. Thus anyone who holds the shares owns the company and its assets, including bank accounts.

Bearer shares are illegal under U.S. securities laws because they make it impossible for regulators to determine who owns the company.

Though Young & Wilcox's address turned out to be a garage, it had at least two bank accounts, one at Chase Manhattan Bank in New York and one in Switzerland, according to the documents.

The documents show that Rose paid Pyne $10,500 with checks drawn on the Chase account in 1975 and 1976. Rose told Jamaican investigators that the money was a loan to Pyne, embassy officials said.

Rose also claimed that Young & Wilcox had nothing to do with his work at Jamaica Nutrition, the Jamaicans said. They have been unable so far to learn any other details about the company.