Federal and state investigators are unraveling a black market currency scheme involving a Washington nonprofit youth organization whose trustees include several prominent Washington residents.

The U.S. Attorney's office for the District of Columbia, the Michingan attorney general and the U.S. Customs Service are looking into activities of Youth for Understanding, a volunteer agency that arranges for 7,000 students a year to study in foreign countries. Founded in Ann Arbor, Mich., in 1952, YFU moved last year to a $13 million headquarters at 3501 Newark St.

A federal court in Brooklyn, N.Y., this week issued a bench warrant for the arrest of the president of YFU's Brazilian affiliate, Sansao Periera, who was scheduled to go on trial last Monday on currency smuggling charges, but failed to appear.

Periera was indicted in July after being arrested May 23 by U.S. Customs agents as he boarded a plane for Brazil at New York's John F. Kennedy Airport.

At the time he was arrested, Periera was carrying $300,000 in $100 bills, funds that YFU officials admit came from the organization's bank account at National Savings and Trust in Washington. Periera had not reported the cash to customs. Anyone taking more than $5,000 cash out of the country must report it.

Accompanying Periera when he was arrested was Robert L. Hussa, then the director of financial affairs and treasurer of Youth for Understanding.

Hussa had blown the whistle on Periera. He told customs agents in advance that Periera was planning to try to take a large amount of cash out of the country.

In a civil lawsuit he has filed against YFU, Hussa charges the cash smuggling trip was the first step in a black market currency scheme designed to make money for YFU.

Hussa contends in the suit that Periera and Philip H. Yasinski, then president of YFU, planned to take the cash to Brazil and sell it on the black market for Brazilian cruzeiros, where the dollars would bring about 20 percent more than the official exchange rate.

The black market dealings were expected to make a $60,000 profit, Hussa says.

The Brazilian currency -- including the $60,000 bonus -- was to have been deposited to a YFU bank account in Brazil, then converted back to dollars and returned to the United States.

If the scheme had worked, Hussa contends, there were plans to repeat it, making a 20 percent profit for the organization every time.

Since Periera's arrest ended the black marketing plan, Hussa has been fired by the trustees from his $37,000 a year job as treasurer of YFU.

The trustees also replaced Yasinski as president shortly after the incident, but he has now been temporarily reinstated as a consultant earning his old $45,000 a year salary. Yasinski could not be reached for comment.

Named president of the organization was John Richardson Jr., who was president of Radio Free Europe from 1961 to 1968 and Assistant Secretary of State for Educational and Cultural Affairs from 1969 to 1977.

In an interview Wednesday, Richardson acknowledged that firing Hussa -- who exposed the black market scheme -- and keeping on Yasinski -- who Richardson himself says was involved in the plan -- is "a very easy thing to misunderstand from outside.

"From inside the organization it looks different," said Richardson. He said Yasinski was rehired, "at my request to help me through a very difficult transition." Yasinski had run YFU for five years, Richardson said, and his knowledge of its activities was essential to keep the $10 million a year operation running smoothly.

Hussa was kept on the payroll for several weeks after Periera's arrest but was dissmissed -- with three months' severance pay -- because "it was impossible to reintegrate him into the organization after this incident," Richardson said.

Before Hussa was fired, his lawyer wrote YFU saying Hussa would quit in return for five years severance pay. When that offer was rejected, Hussa sued.

Richardson said the incident has been "very damaging, very damaging" to YFU. In Michigan -- where the incident has been reported by Ann Arbor News writer Robert Lewis -- Richardson said YFU has lost the services of volunteer workers and found its contributions cut back.

The Michigan-based organization could lose its authority to solicit funds in its home state as a result of an investigation now underway by that state's attorney general.

Assistant Attorney General Ronald Koplansky said Michigan officials are questioning the decision of YFU's board to keep on Yasinski and fire Hussa, and other charges raised by Hussa.

Because it is a Michigan corporation, YFU could have its license revoked if Michigan officials find irregularities. The state has one of the toughest laws in the nation governing charitable groups.

The organization was founded by the Michigan Council of Churches in 1952 and since then has enabled 60,000 students to study abroad. YFU arranges for American students to live with families abroad and study there and also brings foreign students to the United States to study and live with American families.

Richardson said 90 percent of YFU's funds come from fees charged to participating students and the remainder is raised from contributions, including scholarships and grants from a number of major corporations.

YFU purchased its headquarters in Northwest Washington -- the former National Cathedral boarding school for girls -- after a fund drive was launched by former Ford White House aide L. William Seidman.

Among other prominent Washington board members of YFU are Mrs. William P. Rogers, wife of the former Secretary of State, former Sen. Hugh Scott and former Rep. Peter H. B. Frelinghuysen.

Another former Ford administration official, ex-White House Counsel Philip Buchen, was called in to investigate the operation after Periera was arrested.

Richardson said the Buchen inquiry -- and an audit by Arthur Anderson & Co. -- "found nothing" to indicate YFU's board members knew of the plan.

Richardson said the investigation indicated Periera and Yasinski "were trying to help the organization" and would not have personally profited from the transaction. Periera is a wealthy Brazilian whose family launched the YFU program in that country, he added.

The audit, Richardson acknowledged, showed a similar currency exchange incident occurred "some time ago" involving a "a very small amount of money."

But Hussa, the fired treasurer, insists there was "more than one previous" black market deal "and it was a lot of money."

Federal investigators in Washington and New York are still pursuing the case.

U.S. Customs officials reportedly are nestigating a possible conspiracy to violate U.S. currency transfer laws. Hussa -- who went to Customs when he first learned of the plan -- is still cooperating with federal investigators.

Federal authorities in New York still have the $300,000 in YFU funds that Periera was carrying when he was arrested. YFU hopes to get the money back, Richardson said.