A staff member of the D.C. Minority Business Opportunity Commission has resigned after an internal city probe found he had received $5,350 that was provided in part by a contractor whose firm was under investigation by the agency.

Alberto Gomez, a $27,748 program analyst, said he resigned Aug. 31 after commission Director Maudine Cooper accused him of violating the city's conflict-of-interest laws. Gomez denied any wrongdoing, saying that $5,000 was owed to him and the remaining $350 was a wedding gift.

The commission, which oversees the District's minority contracting program, rules on applications by firms seeking certification as participants. Last year $185 million in city contracts -- 39 percent of total contracting -- went to minority firms. Gomez was hired by the commission in April 1984 to investigate the background of firms applying for certification and to make recommendations to the board.

In October 1985, Gomez said, he received a $5,000 check from the Hispanic American Contractors Association, an organization that employed him as executive director from January 1983 to April 1984.

Eduardo Perdomo, chairman of contractor group and president of the construction firm Perdomo & Associates Inc., said he contributed half of the money to the group and that Alexander Beiro, president of A.A. Beiro Construction Co. and a member of the group, contributed the other half.

At the time, the commission was considering whether to revoke the Beiro company's certification after receiving a complaint in July 1985 that the firm failed to meet the requirements as a D.C.-based operation, according to commission records.

As the staff member who prepared the original recommendation to certify the firm in January 1985, Gomez provided information for the investigation of Beiro's firm and defended the firm's qualifications. The complaint was dismissed in December 1985.

Six months later, Gomez was assigned to review an application for certification from Capital Construction, a firm formed by Perdomo's son Carlos and daughter Elaine Jewell. The firm was certified in June 1986.

Gomez said he was owed the money because officials of the contractor group suggested that he would receive a yearly salary of $30,000 when they hired him, but the struggling organization could pay him only $4,000 for about 15 months of work.

Gomez said that after he was hired by the commission, he asked Perdomo about getting paid and Perdomo told him to submit a bill. He said he wrote down hours amounting to more than $5,000 but left out the remainder of the time he worked because he knew the organization could not come up with the money.

Gomez said he did not know at the time he accepted the check that Perdomo and Beiro had contributed the money. He said the payment did not influence his recommendation on whether to certify the firms owned by Perdomo's children and by Beiro.

He acknowledged failing to disclose $5,000 as income on his 1986 tax return, but said he amended the form later.

"In my mind, in my consciousness, it was legitimate," he said. "I had worked. I just didn't get the money while I was in the organization because they didn't have the money."

"Really thinking about it," he said, "it didn't look like the best of judgment since they were doing business with the District government. But I didn't have the authority to grant them business or give them anything they couldn't get anyway."

Beiro and Perdomo, who signed the $5,000 check as the president of the contractor group, said they personally contributed money to pay Gomez because the other businesses in the association could not afford to.

Beiro said he was "not a very active member of the organization" and "didn't really know" Gomez, but felt that "something had to be done. He was underpaid to the nth degree for the work he did."

Beiro said his pending case before the commission "never entered my mind for one moment," when he contributed the money for Gomez. "We qualified by definition," he said.

"What's he going to do for us?" Beiro asked. "He was just shuffling paper as far as I know."

Gomez said he received a second check from the organization for about $350 in about November 1986, a month after he was married, as a gift.

The internal affairs unit of the D.C. police department began an investigation of the checks to Gomez last spring. Sources familiar with the case said police officials turned over their findings to U.S. Attorney Joseph E. diGenova's office and the prosecutors decided not to pursue a criminal case. A spokesman for diGenova declined to comment.

Gomez, who was transferred from his commission job to the city's Office of Human Rights during the investigation, said he believes he was cleared of any wrongdoing. But Maudine Cooper, the commission's director, told him in a meeting last summer that "I had to answer to charges of violating the city's conflict-of-interest laws," he said.

Gomez said he chose to resign because "she had her mind made up" and there "was really nothing else that could be done."

Cooper declined to comment, saying personnel matters are confidential.