The Diplomat National Bank of Washington was secretly and fraudulently controlled from its beginning in 1975 by a small group that included accused South Korean agent Tongsun Park and the closest aide of South Korean evangelist Sun Myung Moon, the Securities and Exchange Commission charged yesterday.

Park, who has been indicted on conspiracy and bribery charges in the South Korean influence-buying investigation in Congress, bought 10 per cent of the bank's initial stock offering through front men, and Bo Hi Pak, the aide to Moon, controlled another 43 per cent of the stock through others, the complaint alleges.

When they applied for a charter, the bank's founders told the comptroller of the currency that no person would control more than 5 per cent of the stock.

In addition, the complaint charged, Charles C. Kim, the bank's chief operating officer until his resignation under fire in April, lied to the comptroller's office during an investigation of the stock's true ownership.

The bank also failed to disclose to prospective stockholders that Moon's Unification Church had $2.5 million in deposits - nearly half the bank's total - at the end of last year, or that the bank had never made a profit, the SEC says.

The bank and Kim have agreed to stop all activities cited in the SEC complaint, without admitting or denying them. The bank also agreed to expand its board of directors.

Others named in the complaint - Park, Pak and Speneer E. Robbins, a close, Park aide - were expected to agree soon to the SEC conditions.

Referrals for possible criminal prosecution against Kim seem likely, since that is the general practice of the comptroller's office when it finds false statements about bank charter proceedings or investigations have been made.

The bank issued a statement yesterday through its attorney, Philip N. Smith Jr., nothing that current manage- ment "has not been accused of wrongdoing by the commission . . . The bank believes it is clear that it was a victim of, not a participant in, any improper conduct."

The bank is located at 2033 K St. NW.

The SEC investigation began several months ago after press accounts of the involvement of Moon and Park in the original stock offering. A House International Relations subcommittee headed by Rep. Don Franser (D-Minn.) also has been examining the original financing of the bank to see if the South Korean Government somehow directed a stock takeover.

Sources familiar with the several investigations say there is evidence the KCIA was involved in financing the bank.

In a related development a spokesman for the Fraser subcommittee confirmed yesterday that it had been questioning a Korean Central Intelligence Agency officer who headed operations in New York City. The official Sohn Young Ho, sought the protect on of U.S. authorities earlier this month, reportedly because he had been ordered back to Seoul during a shake-up in the KCIA hierachy in the United States.

It is not known whether Sohn has any knowledge of the South Korean government's attempts to influence U.S. policy in Washington.

He is the second KCIA official to seek refuge in the United States. Kim Sang Keun, an embassy official in Washington, defected last fall and has been cooperating with the Justice Department in its criminal investigation of the South Korean lobbying effort.

The Diplomat National Bank was organized in 1975 as the first Asian-American bank in the Washington area. Its organizers included syndicated columnist Jack Anderson, who reisgned from its board of directors last fall after criticism that the bank role conflicted with his job as a newsman.

The SEC complaint charges that the bank's fraudulent representations to stockholders continued even after news reports of Park's and Pak's involvement led the board to seek the sale of their stock.

Those named in the aocmplaint incorrectly said that Park owned no stock, and that the bank's management was unaward of how he and Pak became investors, the SEC says.

In a related development yesterday, Rep. Bruce F. Caputo (R-N.Y.) a member of the House committee cinvetigating the influence-buying campaing on Capitol Hill, launched a stinging attack on the pace and scope of the committee's inquirey.

Angered because the committee staff had refused to show him confidential documents obtained by the Central Intelligence Agency, Caputo charged that the members had lost control of the investigation. He also criticized former Watergate special prosecutor Leon Jaworski, the committee's special counsel, for providing only part-time leadership to the investigation.

Because of the problems, he said, the committee investigation seemed to be concentrating on only a few former members, rather than the "dozens and dozens" of current members who were guilty of at least technical violations of House ethical standards becasue they accepted cash or gifts from the South Korean lobbyists.

Caputo has criticized the pace of the investigation before, but not in as deliberate a fashion.

He invited reporters from six newspapers into his office to hear his complaints, he said, because he was frustrated by his inability to convince other members of the committee of the need to urge the investigation along.

Jaworski issued a statement in response, saying "I regret that Mr. Caputo, whether due to ignorance or of the facts, or to seeking self-serving publiucity, has made statements that are totally without foundation."

The committee is scheduled to meet today.