South Korean President Park Chung Hee and several U.S. congressmen have long known that businessman Tongsun Park was working as an agent of the Seoul regime, according to exchanges of letters in 1973 between the congressmen and President Park.

The letters provide the first documentary evidence to contradict public denials of Tongsun Park's role, by both President Park and some of the congressmen under investigation by the Justice Department for accepting cash, gifts and campaign contributions from Tongsun Park.

The correspondence, copies of which were obtained by The Washington Post from nongovernmental sources, includes letters written to South Korean President Park by Sen. Joseph M. Montoya (D-N.M.) and Reps. Cornelius E. Gallagher (D-N.J.), Otto E. Passman (D-La.) William E. Minshall (R-Ohio), Richard T. Hanna (D-Calif.) and John J. McFall (D-Calif.). All but McFall have since left Congress.

All five of the present and former House members are under investigation by the Justice Department, which also has copies of their letters to President Park. Montoya is not known to be under investigation.

The letters from the congressmen to South Korean President Park contain glowing reports of Tongsun Park's success in lobbying Congress and the Nixon administration on behalf of South Korea.

At that time, Tongsun Park was publicly known only as the host of lavish Georgetown parties attended by many Congressmen and administration officials. He was not a registered representative of the South Korean government, as U.S. law requires for a foreign agent lobbying U.S. government.

A Feb. 24, 1973, letter from Gallagher to South Korean President Park claims that Tongsun Park had received personal commitments of continued U.S. military aid to South Korea from U.S. Defense Secretaries Melvin Laird and Elliot Richardson.

Laird and Richardson told The Post that they made no such promises. But Gallagher, who had just left Congress at the time and was facing jail on tax evasion charges, wrote President Park that Tongsun Park had used their support to gain acceptance from key House and Senate leaders.

With Tongsun Park and his allies in Congress, Gallagher told the South Korean president, "you have an extremely competent team working on your behalf and making things come out right for your country."

Minshall, who was then the ranking Republican on the House Defense Appropriations Subcommittee, wrote on Feb. 23 that "our good friends" Laird and Tongsun Park supported U.S. aid to South Korea. But he also mentioned a hostile mood in Congress and added, "We are counting on you Mr. President, for your continuing support for Tongsun's work here in Washington."

Hanna, then a key member of the House international trade and finance subcommittees, wrote President Park on Feb. 21 to recommend using the South Korean Embassy here "and such other supports as will assure the sympathetic and directed assistance friends of Korea here in Congress" to head off possible trade barriers to Korean goods.

Hanna even sent a copy of that letter to the director of the Korean Central Intelligence Agency, seeking concurrence for this strategy on altering U.S. trade policy for South Korea's benefit.

Letters of response from President Park thanked the U.S. congressmen for their work in support of his nation. President Park, who has since consistently denied that Tongsun Park had any connection with his government, told Passman in 1973: "It is good to know that you are receiving the fullest cooperation and assistance from Mr. Tongsun Park in this field (rice sales) and others."

The Washington Post also has been told in recent interviews that Tongsun Park received regular instructions from President Park through embassy channels and that the South Korean ambassador here, Kim Dong Jo, was told by President Park as early as 1971 to cooperate with Tongsun Park.

In addition, the Capitol Hill-Seoul correspondence obtained by The Post includes transmittal letters from Ambassador Kim that indicate the messages were sent through diplomatic channels.

Kim Su-doc, cultural and information counselor for the South Korean Embassy in Washington, said yesterday that his government declined to respond to Washington Post questions about the exchange of letters. "It is our consistent position not to make comment on any personal correspondence between the head of state and congressmen," he said.

The Washington Post reported last fall that U.S. intelligence sources discovered in 1970 that President Park planned to use commissions Tongsun Park earned on rice sales to finance an elaborate campaign to buy influence with American public officials.

Tongsun Park generated some $8 million over four years in the early 1970s from just one U.S. rice exporter. The South Korean government "required" Park's services on all rice sales to that country.

U.S. State Department officials expressed concern this week about the propriety of the letters from the Congressmen to President Park, especially since Tongsun Park was not a diplomat or a legally registered representative of the South Korean government.

"I don't think you'd see most members of Congress writing letters like that to the lobbyist for a corporation or labor union in his own district, much less to a foreign head of state," one State Department congressional relations official said.

Investigators for the House Ethics Committee, which is investigating House members' ties to the South Korean lobby, also have expressed interest in the letters because they detail individual congressmen's knowledge about Tongsun Park's lobbying.

In a memo to the committee last month, special counsel Philip A. Lacovara pointed out, for example, that a section of the Foreign Agents Registration Act holds that if members lobbied for South Korea at Tongsun Park's request, they could be considered foreign agents themselves and liable for criminal penalties. A $10,000 fine and two years in prison are possible penalties.

"Since a member of the House is elected to represent the interests of his voting constituents and of the people of the United States as a whole," Lacovara wrote, "any finding that he actually acted as an agent for a foreign government could justify severe punishment, whether or not the acts were themselves corrupt."

There are indications that Tongsun Park's congressional friends were asked to write the laudatory letters to President Park -- all dated within a few days of each other -- because the unofficial lobbyist was in some kind of trouble back home in South Korea.

It is known, for instance, that a rivalry of sorts existed between Tongsun Park and South Korean Ambassador Kim. A former embassy official, Lee Jai Hyon, recalls that Kim and other diplomats often complained privately about Tongsun Park's activities.

But in 1971, Lee said in a recent interview, the ambassador showed him a page of a hand-written letter from Park Chung Hee. "It said, in effect, 'Don't quarrel with Tongsun Park but give him good cooperation,'" Lee recalled.

Tongsun Park's lobbying activities were so blatant at times that Philip C. Habib, U.S. ambassador to South Korea from 1971 to 1974, reportedly complained to high Korean government officials about him, and warned visiting congressmen to stay away from him.

Although it was not known publicly at the time, Tongsun Park's close ties with Rep. Gallagher may have been a problem for him by late 1972, when Gallagher pleaded guilty to income-tax evasion charges on several hundred-thousands of dollars in bonds. The Washington Post reported last year that Gallagher told a grand jury in 1972 that Tongsun Park had helped him cash $16,000 worth of the bonds the year before.

In any case, by early 1973, Tongsun Park apparently was sufficiently worried to ask some of his Capitol Hill supporters to write President Park on his behalf. Former employees of Minshall and Hanna, for example, recall that Park brought sample letters by their office about that time.

Here is a closer look at the congressional letters to President Park Chung Hee and at the writers' associations with Tongsun Park: Rep. Cornelius E. Gallagher

At the time he wrote a rambling, four-page, single-spaced letter on congressional stationery, Feb. 24, 1973, Gallagher was, as he delicately put it, "temporarily out of the Congress." Two months earlier, Gallagher had pleaded guilty to the tax evasion charge.

In his glowing report to President Park about Tongsun Park's lobbying skills, Gallagher even called him "sort of an Asian Henry Kissinger without a German accent."

"I tell you this not to praise one person but so you know that you have an extremely competent team working on your behalf and making things come out right for your country," Gallagher wrote to President Park. "Nothing, as you know, happens without a great deal of work and support."

Sources close to former Defense Secretaries Laird and Richardson dispute Gallagher's claim in this same letter to President Park, that they had made promises to Tongsun Park about U.S. aid to South Korea.

Laird has been quored in the past as saying that he had first been alerted by intelligence reports in 1970 that Park was a South Korean agent and had communicated his concern about Park's congressional lobbying activities to the State Department at that time.

Richardson said last week that no such warning had ever been passed along to him and that he had never known such intelligence reports existed. "I never knew who (Tongsun Park) was," Richardson said.

A check of Richardson's appointments diary for Feb. 24, 1973 -- the date Gallagher says Park was summoned by Richardson -- shows it was Saturday, and Richardson did not go to his office.

Richardson said he thinks "it is certainly outrageous" for his name to have been used falsely in letters to a foreign head of state. "It is a shock to me," he said, "to find that this has been done."

Richardson added he had been to only one George Town Club party staged by Park, an April 16, 1973, black-tie dinner celebrating Rep. McFall's election as House Whip. Tongsun Park founded the company that operates the George Town Club.

Laird accepted an honorary membership in the George Town Club while he was Secretary of Defense and used it frequently to entertain visiting foreign dignitaries, including his counterparts from Japan and Germany. He also gave a party there for President and Mrs. Gerald Ford shortly after they moved into, the White House.

After leaving the government and going to work for Reader's Digest, Laird took out a private George Town Club membership and still uses the club.

Gallagher was one of Tongsun's Park first friends on Capitol Hill. In 1971, when Gallagher became chairman of the Asian and Pacific Affairs Subcommittee, he had as a member of his personal staff a relative of Tongsun Park named Kim Kwang, who had worked for Hanna the year before. Other staff members at the time recall being puzzled about what Kim's duties were besides traveling with Gallagher to the Far East.

About that time, the State Department was told that National Security Agency intercepts of South Korean diplomatic cable traffic mentioned Kim as an intelligence operative. When he and Tongsun Park tried to accompany then House Speaker Carl Albert (D-Okla.) on a visit to South Korea that fall, the State Department protested, and they were forced to travel separately.

Gallagher has remained closely associated with Tongsun Park since being released from prison in November, 1974. He has continued to stay in Tongsun Park's homes here and in the Dominican Republic and sue Park's chauffeured limousines and his office facilities.

Tongsun Park also gave Gallagher a $250,000 unsecured loan to invest in a pork slaughtering venture in 1975.

Gallagher has declined to answer reporters' questions since his records were subpoenaed last year as part of the South Korean lobby investigation. Rep. William E. Minshall

Minshall began his Feb. 23, 1973, letter to South Korean President Park by expressing his "great delight" that the South Korean leader had just been re-elected.

To assure peace in Asia, Minshall wrote President Park, "our allies must be helped to maintain an adequate level of military strength. As you know so well, such strong beliefs have been shared by our good friends, Secretary of Defense Laird, and Tongsun Park."

As the new Congress approached defense issues, Minshall added, "we are hoping that the kind of understanding, support and enthusiasm which the Pentagon has demonstrated in the past will continue under the new Secretary of Defense Elliott Richardson. As a matter of fact Tongsun and I will be seeing the new Secretary as soon as he returns from Korea."

Richardson said Friday that there was no such meeting.

Minshall then warned President Park in his 1973 letter that Congress, especially the Senate "still would not be in a receptive mood" to administration proposals to aid South Korea.

"Of course, it goes without saying." Minshall wrote, "Korea needs all the assistance she can muster from her American friends, and in this regard, as it has been mentioned before, we are counting on you, Mr. President, for your continuing support for Tongsun's work here in Washington."

Minshall, who left Congress in 1975 to become a lobbyist for the Northrop Corp., a major defense contractor, could not be reached for comment despite repcated calls and visits to his home and office over the past several weeks.

The Washington Post reported in December that the Justice Department was questioning Minshall and his staff about his relationship with Tongsun Park. In an interview then, Minshall acknowledged socializing with and writing letters and arranging interviews for Tongsun Park. But he denied ever accepting any money from him.

In the fall of 1970, Minshall arranged a meeting with Defense Secretary Laird, his old friend from the House defense appropriations Subcommittee, for Chung Il-kwon, a top South Korea government official. The State Department had turned down the request earlier, but Tongsun Park then asked Minshall to intercede.

In a March 16, 1973 reply forwarded through Ambassador Kim, President Park told Minshall he "sincerely appreciate(s) your effort to win the continuing support of the Department of Defense and the American administration" in honoring the U.S. commitment to South Korea. Rep. Richard T. Hanna

In his Feb. 21, 1973, letter to the South Korean president, Hanna said he felt there had been a shift in emphasis from military to economic matters as the most important aspect of U.S. Korean relations.

He outlined proposals in Congress for trade restrictions such as quotas and selective tariffs on imported goods. "All of this is to indicate to you, Mr. President," Hanna wrote to President Park, "that we are facing a critical time when the first skirmishes of a trade war are in the offing."

He said it was hard to predict what actions would be taken. "What is clear, however, is that an early warning system must be in place," Hanna told the South Korean president. "The dangers and impacts on the Korean economy could be of such a scale, without appropriate protection of exemptions and exceptions, as to destroy much of what your administration is achieving."

Thus, Hanna told President Park, "I strongly recommend that you be prepared to use all the resources of your embassy and join with that office such other supports as will assure the sympathetic and directed assistance of friends of Korea here in the Congress in the particular legislative and executive actions.

"The time to bring your friends to bear on the problems is while the measures for action are being formulated. After the committee has acted or the executive decides, it is too difficult and sometimes too late to affect changes."

Hanna added that he had discussed the matter with "our mutual friend Tongsun Park. He agrees with me that conditions dictate a very active presence for Korean interests" in these proposals.

Hanna said he was also sending a copy of the letter to "Director Lee' (Hu Rak), who was then head of the Korean Central Intelligence Agency.

"I am sure that his (KCIA chief Lee's) information will support my appraisal relative to the important moves which could be made in this session of Congress," Hanna said.

In his March 16, 1973, reply, President Park said he agreed with Hanna's assessment about the shift in emphasis toward trade policy: "We should prepare ourselves for this change and our moves and actions should be well-timed as you rightly pointed out. And we should muster all possible supports from all possible sources in addition to the regular diplomatic channel."

In a brief telephone interview from California last week Hanna acknowledged sending the letter to President Park, but declined to discuss the specifics of it over the phone. He later canceled a scheduled personal interview.

The Washington Post last year obtained copies of six checks totaling $22.500 that Tongsun Park wrote to Hanna in 1973 and 1974. A former Hanna staff member who was recently questioned by the federal grand jury here for 1 1/2 hours about "discrepancies" involving Hanna's income-tax returns testified that such money was customarily treated as "consultant's fees".

She declined to tell a reporter what the discrepancies involved. Hanna himself recently told a Los Angeles Times reporter that he may have made some mistakes in the way certain income was declared.

Hanna has acknowledged being in business with Tongsun Park while serving in Congress. In the last House Ethics Committee report Hanna filed before leaving the House in 1975, he acknowledged receiving more than $5,000 each that year from two of Tongsun Park's firms: Pacific Development, Inc., and Suter's Tavern, which owns the Georgia Town Club.

However, Hanna never removed many of his clothes and business papers from a guest room he used regularly in Park's 30th Street NW mansion. Hanna's suits, left hanging in the closet, have been confiscated by the Internal Revenue Service, along with an estimated 300 suits owed by Tongsun Park.

The IRS also confiscated some of Hanna's papers and records along with many cardboard cartons of private files that Park left behind. All this material has been turned over-under subpoena, to the Justice Department.

In addition, one former Hanna staffer recently told the federal grand jury here that Hanna used a Cadillac automobile supplied to him by Pacific Development.

Hanna and Tongsun Park had severed their business connections last year, when Park's troubles with the Justice Department investigation were just beginning. "That young man is going to meet his Waterloo," Hanna said at the time about Tongsun Park, whom he referred to as an "oriental Gatsby." Hanna added, according to a friend. "I don't intend to be around when it happens." Rep. Otto E. Passman

Passman, the powerful head of the House subcommittee that approved foreign aid funds at the time, wrote President Park on Feb. 20, 1973, saying, "Mr. President, may I take the liberty of once again bringing to your attention the very effective manner in which your countryman, Tongsun Park, has performed in the United States in behalf of Korea.

"Tongsun Park is a knowledgeable and dynamic individual and what he has been able to accomplish for Korea in recent months in the consummation of rice purchases is phenomenal."

The congressman also noted that South Korea's large purchases of ice, cotton and soybeans "greatly helped" Passman's state and district. "I hope this mutually advantageous arrangement between our countries, with the help of Tongsun Park, may continue."

In his March 16, 1973, reply to Passman, President Park said he shared Passman's satisfaction over the rice purchases. "It is good to know that you are receiving the fullest cooperation and assistance from Mr. Park Tongsun in this field and others," he said.

Passman, who was defeated last year in a Democratic primary, has declined to talk with reporters on the advice of his lawyer, James Hamilton.

From his position as head of the House Foreign Operations Appropriations Subcommittee, Passman exerted great influence on U.S. foreign aid funding. He paid special attention to the Food for Peace program because of its federally subsidized financing of U.S. rice sales overseas.

He is a long time friend of Grover Connell, head of the company that paid Tongsun Park $8 million from 1972 to 1975 for "assisting" its sale of rice.

And Passman has been accused of pressuring countries to change their shipping agents for Food for Peace shipments. Rep. John J. McFall

McFall's Feb. 23, 1973, letter, like Passman's, was prompted by Tongsun Park's prowess as a middleman on rice sales. McFall first expressed his appreciation for South Korea's purchase of California's entire exportable rice crop for 1972.

He then commended "the contributions and assistance of Tongsun Park in meeting and resolving the problems arising from those private purchases and the policies of the U.S. Department of Agriculture. His participation was invaluable," McFall wrote.

McFall said he was "hopeful" that his new position as the majority whip in the house "will allow me to give more meaningful assistance in those areas where the interests of your country and mine converge."

McFall closed by saying, "We will continue to look to Tongsun Park for cooperation in all areas of our mutual interest."

A few months before that letter was written, McFall had accepted $1,000 in cash from Tongsun Park and put it in a secret office account because, he said later, he thought it was illegal to accept it as a campaign contribution.

On April 16, a few months after writing the letter to President Park McFall was the guest of honor at a party at Tongsun Park's George Town Club and received gifts, including a sterling silver tea set.

During the fall of 1974, McFall received another $3,000 in $100 bills from Tongsun Park, again putting the money in his office account.

McFall refused to be interviewed by The Washington Post about his letter to President Park. He demanded written queries, and then did not answer them. Sen. Joseph M. Montoya

Sen. Montoya's Feb. 23, 1973, letter to President Park opens with thanks for "your thoughtful and generous gesture in memory of my late brother," which was "extended through my good friend Tongsun Park."

Montoya, a member of the Senate Appropriations Committee at the time, said that he saw diminished support in Congress for foreign aid programs.But, he added, "with others here in the Senate and with support from the executive branch, Tongsun and I feel," that aid to South Korea would be continued.

"You may be sure Mr. President," Montoya told Park Chung Hee, "that in the course of the strategy we anticipate" the truth of Korea's strategic importance would be given appropriate emphasis.

"I personally asked Tongsun to reassure you that, I for one, along with many of your loyal friends in Washington will do all we can to achieve the final goal" of modernizing the Korean military.

Montoya added that Tongsun PArk had briefed him about recent "political reforms" in Korea and he said he hoped to make a trip to South Korea in the near future "so that we might explore further matters of mutual interest which Tongsun has brought to our attention. . ."

Efforts to reach former Sen. Montoya last week at this home and office in Santa Fe, N.M., were unsuccessful. His wife said he would be away for several days and could not be reached.

Mrs. Montoya told a reporter that she had no idea what "generous gesture" President Park had made through Tongsun Park had made through Tongsun Park in memory of her late brother-in-law.

The former Montoya staff member whose initials indicate that she typed Montoya's letter to President Park said that she has no recollection of ever having seen the letter before. Handling a Xeroxed copy of the letter, she said "the language doesn't sound like the senator would have dictated it himself -- he doesn't talk that way."

Although aides sometimes dictated Montoya's letters, she said, no one would have presumed to have corresponded with a foreign head of state in Montoya's name.

Tongsun Park, the former Montoya staff member said, was a frequent visitor to the senator's office through the years. Also, she said, the senator and Tongsun Park were "social friends".Collage shows Tongsun Park and Excerpts of letters written by friendly U.S. congressmen. At right, Reps. Minshall, Hanna and McFall are shown celebrating McFall's election as House whip at the George Town Club on April 16, 1973., By Hal Hoover -- The Washington Post; Picture 3, 4, Tongsun Park is shown, left, having dinner with Otto E. Passman in Korea in 1972, and right, greeting Cornelius E. Gallagher there last year; Picture 5, Sen Joseph Montoya is shown with Tongsun Park at a George Town Club party.