Last Sunday, five members of something called the "Committee of Concerned Clergy" took out full-page advertisements in four of the nation's largest newspapers -- including The Washington Post -- denouncing the Ayatollah Ruhollah Khomeini and seeking support from readers.

But what the nearly $70,000 worth of ads did not say was that the five were not exactly the religious figures they claimed to be.

In fact, two of the five have been under investigation by police departments around the country.

The five "clergymen" are:

The "Reverend John A. Busse, THM," who has been indicted for third-degree burglary, third-degree robbery and petty larceny in Staten Island, N.Y. In the ad, Busse's affiliation was given as "Eastern Orthodox." While a branch of Christianity is referred to as Eastern Orthodoxy and has many different churches within it, there is no Eastern Orthodox Church.

A "Bishop Demetrius, PhD," who also purports to be affiliated with the Eastern Orthodox Church and who is under investigation by Staten Island District Attorney Thomas Sullivan. Demetrius has initiated a variety of schemes around the country that have taken advantage of confusion about the many divisions of Christianity, particularly Eastern Orthodoxy. He has been defrocked as a priest and excommunicated by the head of the Ukrainian Orthodox Church in the United States, Metropolitan Mstyslav.

A "Bishop James E. Burns, DD Episcopalian, New England States," who is not listed in the current directory of the Episcopal Church, which does not have a "New England States" jurisdiction.

The "Reverend Samuel Farrell, THD, Presbyterian, Southern States," who insisted to a caller that he was a minister of the Presbyterian Church in the United States, but is not listed in the current directory of that church.

A "Bishop D. J. King," who also identified his affiliation as the Eastern Orthodox Church.

The denominational identification of the committee members was not included in all four ads. A man who said he was Demetrius subsequently complained to The Post that the paper had made a mistake by including the affiliations.

The advertisements appeared in last Sunday's editions of The Post, The New York Times, the New York Daily News and the Los Angeles Times. They made no specific request for funds, but they included a coupon at the bottom for readers to send in "if you agree with us." In addition, there was a boldfaced reminder that "This announcement is made possible thru tax-deductible contributions."

All the newspapers required cash or a certified check before they would accept the ads.

In the dark windowless lower Manhattan room that is the committee's office, Demetrius expressed surprise that some readers had viewed the advertisement as a suggestion to send money, "especially since we did not ask for donations," he told a visitor.

He said the office has received between 1,000 and 1,500 letters a day since the ads appeared. When pressed by a reporter to estimate the amount of money he had received, he abruptly changed the subject.

When asked where the group got the money to purchase the ads, Demetrius replied, "From private donations . . . from people who feel as we do," and again changed the subject.

Because of the ads' language favorably comparing the regime of the deposed shah of Iran with Khomeini's, American church leaders have speculated that the ads are being financed by pro-shah groups.

The speculation was fed by the mystery surrounding the organization and its five-man executive committee. "I've looked through all the directories and I can't place any of them," noted Constant H. Jacquet Jr., editor of the Yearbook of American and Canadian Churches. As long-time compiler of that prime sourcebook, Jacquet is the country's leading authority on religious organizations.

The day after the advertisements ran, Farrell took phone calls at the office, telling a caller that Demetrius was "in Chicago" or, a little later, "on the way to Chicago." When pressed for details of the organization, he offered to take the caller's name and number and have Busse return the call.

But a few minutes later, Farrell called back to announce that questions would be answered only if the inquirer sent in "one of the coupons that came in the ads . . . I'm sorry, that's what I was told by the other gentleman in the office." When questioned, he hung up.

Despite Farrell's contention that the organization has been around since 1922, the telephone company said the committee's office phone was "a new listing." The office, strewn with boxes full of envelopes and a few pieces of battered furniture, had the look of a new enterprise.

Demetrius, however, has a long history of enterprises in this country.

He immigrated to this country in 1969 and followed a variety of pursuits, turning eventually to the church.

Flourishing what one church leader called "a thousand certificates and diplomas," he convinced the Ukrainian Orthodox Church to take him under its wing.

"Our people are very foolish, very foolish," observed the church's Bishop Mark (Orthodox prelates customarily use only a single name) of Carteret, N.J. But in the defense of his church, he said of Demetrius, "He had a gift of gab -- he would sell you the Brooklyn Bridge."

Demetrius was assigned as priest of St. George's parish in the little Central Pennsylvania town of Minersville.

According to Francis Tominasky, police chief of Minersville at that time, and others, Demetrius began ordering merchandise -- a washer and dryer, a recliner chair, a grandfather clock -- and charged them to the church.

"When the bills came, he just threw them away; it wasn't until after he left that the people (church members) knew what had happended," said the Rev. Omelan Mycyk, the current pastor of St. George's.

Demetrius also took out full-page ads promoting his lectures on the occult, Mycyk recalled. His topic -- and the fact that he delivered the speeches in clerical garb -- offended many of the residents of Minersville, the pastor said.

"To me he looked like Rasputin," said Joe Wallinski, the town's police chief.

In mid-October of 1976, after less than a year in the parish, Demetrius took off, leaving behind him a blizzard of unpaid bills, according to police and Mycyk. In addition, the pastor said, some of the church's liturgical vestments and other religious articles disappeared at the same time.

Mycyk said church members were dissuaded by police from filing charges against Demetrius because "the police said it wouldn't look good for the church to sue -- that it would be better for an individual to do it" Wallinski's recollection is that the church members, already embarrassed by the whole affair, were reluctant to press charges.

Demetrius was then defrocked and excomunicated by the Ukrainian Orthodox Church.

Together with Busse, who he had said was his "brother," Demetrius headed for Miami.

Now identifying himself as bishop of the "Catholic Orthodox Church," according to The Miami Herald, he took an expensive apartment and announced in a large ad in the Spanish language edition of The Herald a massive celebration -- a pontifical mass -- in the city's baseball stadium in honor of St. Barbara, who is greatly revered among Cuban Catholics. He also launched a drive to build a monastery in honor of the saint in the Florida Keys.

Local Roman Catholic and Greek Orthodox church leaders quickly distanced themselves from Demetrius, and admonished their church members to do the same. In the meantime, the check Demetrius had given The Herald bounced, and the paper's reporters began looking into his background.

Less than six weeks after he arrived in Miami, Demetrius vanished, leaving behind, by The Herald's reckoning, about $3,000 in debts and bad checks, the "pontifical mass" canceled and the dream of a monastery shattered -- or at least deferred.

Last year Demetrius, still accompanied by Busse -- now known as the Rev. Busse -- turned up in Staten Island.

In the name of the Third Order of the Holy Catholic Eastern Orthodox Church; Diocese of Miami, Puerto Rico, the Virgin Islands and the Dominican Republic, the pair leased an old mansion on the island and converted it into what they called the Holy Trinity Monastery, according to Staten Island District Attorney Sullivan.

Demetrius' plans for the property are not known, but in the year that he lived there, his "Catholic Eastern Orthodox Church" allowed itself to be confused with established churches.

"He charged things in our name; he causes embarrassment to our people," said the Rev. Paul Schnierle of Brooklyn, the spokesman for the umbrella organization of officially recognized Orthodox denominations in this country.

Sullivan said that Staten Island businesses have complained to his office about Demetrius' church's long-overdue bills, ranging on items from "slabs of marble for the altar [to] an elaborate closed circuit television security system [to] votive candles."

The district attorney would not comment about his own investigation of Demetrius, but it is known that a probe is under way.

Busse, he said, is scheduled to appear in court next week on charges that he stole a television set from an apartment building near the monastery.

The monastery, however, is now in shambles. On the morning of Thanksgiving Day, a fire, later officially ruled to be "of suspicious origin," damaged it severely. Demetrius and Busse have moved their operations across the harbor to New York City.