In an unprecedented action, the influential D.C. police union called yesterday for the immediate suspension of Deputy Chief William Trussell, commander of the Criminal Investigations Division (CID).

The demand came as the furor over Trussell's leadership as chief of detectives developed into a crisis not only for Police Chief Burtell M. Jefferson but also for Mayor Marion Barry, according to the union and administration sources.

"Confidence in your leadership is at a crisis stage," the union told Jefferson in a letter yesterday.

Trussell has been assailed by members of the department's homicide squad who charged that he is "incompetent" and that his "interference" jeopardized several major investigations. Members of the squad also charged that on two separate occasions Trussell, a white man, made a blatantly racist remark.

"Homicide can't operate with Trussell in command. CID will be paralyzed" until the issue is resolved, John Markuns, general counsel of the International Brotherhood of Police Officers, said in an interview.

In the letter to Jefferson and Barry, Local 442 of the police officers' union asked Jefferson to suspend Trussell until after a formal investigation of the allegations.

The union also recommended that Jefferson appoint "an impartial investigator" with the approval of Barry to examine the charges. The union represents 3,000 of the force's approximately 3,800 officers.

"Your failure to suspend Deputy Chief Trussell is contrary to departmental procedure," the letter, signed by Executive Vice President Larry C. Melton, said.

"Certainly any uniformed member of the force, sergeant or below, against whom allegations of incompetency and racial bias were made, would immediately be suspended until such time as a complete and thorough investigation were made."

The union's demand was made shortly after Jefferson concluded an extraodinary, three-hour private meeting yesterday morning with virtually the entire 45-member homicide squad to hear their complaints about Trussell.

Jefferson agreed to the meeting only after the detectives took their complaint to Barry's office.

After yesterday's meeting, Jefferson announced that another full squad session would be held, possibly Wednesday, at which Trussell will be allowed to respond to the detectives' allegations. The detectives voted unanimously to exclude Trussell from yesterday's session.

Outside the meeting room, Trussell declined to comment, other than to say, "the chief of police is handling the meeting. I'm going to abide by all of his orders. . . ."

On Sunday, Trussell called "untrue" the allegation that he had made a racist statement, and said he wanted to hold a press conference to defend himself against all the allegations, Jefferson said yesterday, however, that Trussell had decided on his own not to hold the conference.

After the meeting, Jefferson told reporters that he first learned of the serious nature of the problem last Wednesday during a meeting with a CID union representive.

A union officer challenged Jefferson's assertion yesterday, saying that he had been made "fully aware" of the squad's grievances about six weeks ago.

Melton said Jefferson was told March 27 that Trussell was "interfering and just plain messing up investigations."

That day, Melton said, Jefferson met with the union's 16-member board of directors in Jefferson's conference room at police headquarters.

"At that time, the issue of Trussell was brought up. All the specifics - outside of the later racial issue.. . ." Melton said.

"The chief got rather upset that we were challenging the competence of a superior officer. He threatened to charge several persons with insubordination and there were very heated exchanges over his attempt to protect Trussell," Melton said.

Melton said the chief was told, "If you don't do something about this, it's going to get worse."

Asked about Melton's comments, Jefferson said the meeting was "a matter involving the police department and union matters." He declined to comment further.

The union was one of only three major labor organizations to endorse Barry's mayoral candidacy last year. Political observers credited the endorsement with "polishing" Barry's former image as a radical activist.

Jefferson said Barry called him yesterday morning, and that he told the mayor he was meeting with the detectives to try to resolve the problem.

City Administrator Elijah Rogers said he talked with Jefferson after the meeting, and that Jefferson would be making a full report to him and Barry.

Rogers declined to discuss the homicide squad issue specifically or Trussell's alleged racial remark. However, Rogers said the city administration "would not condone or tolerate" a racial slur by any city employe.

"If in fact a racial slur was made," Rogers said, "Chief Jefferson will find out and will make a report to me and the mayor."

Homicide squad members alleged that in a recent discussion with white detectives about traumatic shock, Trussell said: "Not all people go into shock. Animals don't go into shock and neither do blacks."

It was also charged during the meeting yesterday that Trussell reiterated the remark on a second occasion, police sources said.

Neither Jefferson nor homicide squad members would comment on the details of the meeting yesterday, but sources in the department said it was orderly and respectful on both sides.

"They talked, he listened, and the chief was surprised by some of what he heard," the sources said. The sources also said the detectives brought up, point by point, more than two dozen objections to Trussell's handling of three major cases: the killing of a Capitol Hill woman in her home last February, a triple slaying in Southeast Washington last September and the drowning death of a 5-month-old Swedish baby in the Capital Hilton Hotel last month.

Among other things, the men alleged that Trussell:

Personally "contaminated" a suspected murder weapon by handling it at the crime scene.

Ridiculed the findings of a D.C. medical examiner in one case and declared that there was no need for the medical examiner's office to become involved in homicide cases.

Conducted spontaneous interviews of possible suspects and witnesses at the crime scene without making a written record.

Refused to allow technicians to process the scene of a slaying for fringerprints.

At one point, the sources said, the men asked the squad commander, Capt. Arif Mosrie, to describe the alleged racial remark as he heard it during a discussion of the drowning case.

After describing the incident, Mosrie told the chief that a sergeant and other squad members had reported hearing Trussell make the same remark on a separate occasion. The sergeant confirmed this to Jefferson.

The sources said Jefferson, who is a former Criminal Investigations Division commander, told the men he appreciated their concerns and would take a personal hand in the matter. Jefferson also told the men he thought they were "the best homicide squad in the country," sources said.

One squad member said afterward, "I think we're satisfied that the chief intends to do something about this."

Trussell, 29-year veteran of the force-almost entirely in the uniform division-was appointed by Jefferson last Septemebr to the Criminal Investigations Division command, which includes the robbery, sex offense and burglary squads as well as homicide.

Almost immediately after the appointment, detectives in homicide-generally considered the elite unit in the department-began expressing concern about Trussell's intervention into cases.

The controversy erupted last week when Trussell abruptly transferred veteran homicide Lt. Raymond Pierson, who had argued with Trussell about the handling of investigations.

Squad members said at that time they were "unanimous" in their intention to walk out immediately, but Pierson dissuaded them.

Instead, 42 of 45 men in the squad signed a memorandum to the chief expressing their "collective rage" at the transfer and began organizing a protest campaign to compel Jefferson to intervene.