In a strongly worded letter, the head of the D.C. police officers union asked Mayor Marion Barry yesterday to force police officials to disclose all the findings of an internal investigation of the department's controversial drug testing program.

The letter also called on Barry to conduct a new, independent investigation of the program and take disciplinary action against any officials found guilty of misconduct.

Earlier in the day, union officials released copies of the internal police panel's 50-page report, which Police Chief Maurice T. Turner Jr. has so far refused to disclose. The union said it released the report to underscore its charges that the 17-page summary released by Turner late Friday night was just an "edited, watered-down" version of the findings of the so-called Cox Committee.

"I believe that the chief is taking extraordinary measures to conceal the truth in order to minimize the impact of the investigation on the department's drug testing program and to protect certain MPD officials," Gary Hankins, chairman of the labor committee of the Fraternal Order of Police, wrote to Barry.A copy of Hankins' six-page letter was obtained by The Washington Post through a city government source. "I submit that the chief's handling of this matter has created a crisis of confidence for the department and for your administration."

Barry ordered Turner in summer to investigate allegations of tampering and possible criminal violations in the police department's drug testing program after two clinic workers took their charges to U.S. Attorney Joseph E. diGenova and subsequently to Barry.

Turner responded in August by appointing a three-member panel of police officials, headed by Assistant Police Chief Ronal Cox, to conduct a closed-door investigation into charges that procedures of the department's drug screening program had been manipulated in favor of certain police officers who were up for promotions. The committee, originally scheduled to release its report at the beginning of October when Cox was scheduled to retire, found no basis for the clinic workers' allegations of criminal violations and tampering, and called the integrity of the program "intact."

In the letter that was hand-delivered to Barry and all 13 members of the D.C. Council yesterday, Hankins said an independent team of investigators should probe "whether there was a deliberate effort to conceal evidence or give false evidence and to distort or minimize the results of the investigations."

Hankins, who said FOP members voted Wednesday night about what action to take in regard to the drug-screening report, also asked Barry to order the police chief to release "the entire record of the investigation," including 149 attachments showing the testimony and physical evidence on which the panel made its decisions.

A spokesman for Barry said that the mayor had not had time to read the letter and had no comment on the union's call for an independent investigation, of which Barry was aware. "The mayor will not see {the letter} before tomorrow," press secretary John White said late yesterday afternoon. "I can't guarantee that he'll see it tomorrow."

On Jan 15, Turner announced plans for an official reprimand of Carl V. Profater, assistant chief for administrative services and the department's number three official, and Deputy Chief Jimmy L. Wilson, former head of the internal unit charged with investigating drug use and other corrupt acts among the department's 3,880-member force. Also to receive an official reprimand was Capt. Robert J. Noyes, a former drug screening official.

In a prepared statement issued last night, police spokesman William White III said: "After great painstaking care and lengthy deliberation, Chief Turner made what he felt was the most appropriate decision in this case. The level of disciplinary action taken by the chief for misconduct is a management prerogative that any agency head has the authority to exercise."

Hankins said yesterday that the information the committee had released was "vague, evasive or silent on a number of key issues." He cited in particular the committee's failure to make any recommendation "regarding the possible false testimony" of Profater, Wilson and Noyes to the committee.

"Incredibly, while the Cox committee recommends that the chief take 'appropriate action' regarding the faulty judgment on the part of these officials, the committee makes no recommendation whatsoever regarding the possible false testimony, and the chief of police appear quite willing to overlook this aspect of the investigation . . . ." the letter said.

In the letter, Hankins challenged the mayor to order release of all documents attached to the Cox report and to assign an independent investigator without "vested interest in preserving the drug testing program" to probe problems at the clinic.Staff writer Tom Sherwood contributed to this report.