Two employes of the D.C. police department's drug screening program, who alleged in a confidential letter to Mayor Marion Barry that ranking police officials were tampering with test procedures, were "summarily relieved" of their duties on Wednesday, according to a grievance filed late Thursday with the chief of police.

Yesterday, after inquiries by The Washington Post about the grievance, a police spokesman said that the employes "will return to their duty assignment on Monday."

But he said that the employes, who are scheduled to meet with police union officials, attorneys and the department's labor relations officer on Monday, have not been informed of the department's intention to restore them to their positions.

The employes alleged in a July 28 letter to Barry that police officials and members of the department's Internal Affairs Division manipulated procedures to obtain "desired results." The employes also alleged "misconduct and possible criminal violations" by D.C. police officials, including bribery, tampering with physical evidence and violations of standards of conduct.

Their allegations triggered an investigation by a panel of ranking police officials who have heard testimony from dozens of witnesses in closed sessions. The panel, which is still conducting hearings, is scheduled to submit a written report to D.C. Police Chief Maurice T. Turner Jr., which the chief has said will be made public.

In the grievance, the employes -- the clinic's civilian drug-screening coordinator and an officer who administers the tests -- asserted that the action "is a demotion in rank and was a direct reprisal and retaliation for their participation in the investigation and because they communicated information regarding possible misconduct of {police} officials" confidentially to the mayor.

According to the grievance, Marguerite Anastasi, a 24-year civilian employe of the department who has supervised the screening program since it began in 1982, and Officer Vernon Richardson, a 14-year veteran who performed the tests since 1984, were told in separate meetings Wednesday morning by Lt. Michael Irish, the clinic's administrative lieutenant, that they were "summarily relieved of all duties pertaining to the drug-testing program" because of their letter to Barry.

Anastasi last night declined through a family member to comment, and Richardson could not be reached.

Irish and Inspector Winston Robinson, director of the Police and Fire Clinic at 2 D.C. Village Lane SW, refused last night to comment on the action against their employes.

"I find it ironic that the only action taken so far in this thing is against the people who gave information that initiated the investigation in the first place," said Robert E. Deso, attorney for the Fraternal Order of Police, who wrote a seven-page letter July 16 to U.S. Attorney Joseph E. diGenova detailing the allegations.

Capt. William White III, a police spokesman, said last night that the actions against Anastasi and Richardson will be investigated, but declined to comment on the broader investigation of procedures at the clinic.

The letters to Barry and diGenova described a May 30, 1985, incident in which a lieutenant up for promotion to captain returned in civilian clothes to the clinic for an unprecedented second chance at a drug test after a sample of his urine taken earlier that day tested positive for drugs.

Richardson was ordered to conduct the extraordinary second test by clinic officials and members of the Internal Affairs Division, the department's watchdog, after they received several calls from an unnamed but high-ranking police official, according to the letters.

The lieutenant's second sample was not tested at the clinic, as is routine, but was flown, along with four other samples, to a North Carolina laboratory by a police sergeant for a routine confirmation test. Normally, urine samples are sent by Federal Express to the laboratory.

When the sample was returned from the lab to the clinic, it was reported free of drugs, and the lieutenant received his captain's bars.