The D. C. Office of Human Rights said yesterday that it had decided to seek written information from five well-known Washington nightclubs that it accused Thursday of using discriminatory practices against blacks.

The office not only will ask for written information from the five clubs, but will assign investigators to probe the allegations filed formally last week, according to Anita Shelton, director of the human rights unit.

The Alcoholic Beverage Control Board independently held a four-hour hearing Wednesday to determine whether one of the five clubs -- elan -- violated District statutes that require financial records be kept on the premises and as a Class C restaurant allowing the general public unrestricted admission to the premises.

A Class C restaurant is defined as an establishment that serves complete meals to the public.

Elan attorney Eric Cummings categorically denied the ABC Board charges and said in a conversation with a reporter that the club never has practiced any form of discrimination.

Director Shelton filed complaints of admissions discrimination against elan, Appletree Plum Discoteque, Lost and Found and Phase One restaurants.

Ten of the 29 discrimination complaints against D.C. clubs filed with her office since 1977 involve the five clubs, an aide, John Watkins, said.

Shelton and ABC Board Chairman Robert Lewis also targeted two private clubs, Pisces in Georgetown and Foxtrappe in Northwest Washington, for investigation, according to a document on file in the human rights office.

Shelton said some public restaurants used varying admissions fee schedules and a discriminatory method of collecting them.

"Others are alleged to be applying dress codes, ID requirements in connection with underage drinking laws, and crowd capacity regulations, depending on the time of day or racial quotas for the same purpose," she said last week in the document that outlined the formal complaints against the clubs.

"We're going to take a hard look at Pisces and Foxtrappe, too," Abc Board staff director James Boardley told a reporter yesterday. "They're supposed to be nonprofit and open to members and their guests only. They can't accept $5 from anyone off the street and say, 'come in."

Boardley added that private clubs but not restaurants are allowed to operate in residential areas of the city. If Foxtrappe, which is located in a residential neighborhood, is found to be violating its Class C private club status, it would be breaking the residential statute as well.

Under the D.C. Human Rights Act of 1977, the Office of Human Rights must file formal complaints in order to determine the validity of charges of discrimination.

"By no means are we indicting these places in advance," Watkins said. "These steps are mandated by law."

Under the process, the office must decide within 120 days whether any of the allegations have substance. If "probable cause" is found, it will recommend that the full Commission on Human Rights hold public hearings and decide on the particulars. Its ruling may be appealed to the D.C. Court of appeals.

Should the commission conclude that discrimination has been practiced, the ABC Board then may suspend or revoke a liquor license of the violator.

Ownership of elan has changed hands since the Office of Human Rights held hearings in July on allegations of discrimination at city nightclubs. On Sept. 27, Lance C. McFaddin sold his majority share of the enterprise to Robert Brewer and Farah Malik.

Rep. Charles Wilson (D-Texas) also sold his 5 percent share of elan recently.

"I didn't think that there was any discrimination," he said in Texas. "But it was becoming a real nuisance."