The Washington police homicide branch, once an elite unit that regularly solved 80 to 95 percent of city murders, was able to solve just 64 percent of its cases during the first six months of 1982.

If that rate holds through the year, it would mark the lowest closure rate for the city homicide branch since 1973.

A dozen current and former homicide detectives interviewed in recent weeks attributed the decline in the closure rate primarily to the inexperience of the detectives--half of the 43 have four years or less in homicide--and a general reluctance of the rank and file to take direction from leaders who have scant background in investigating deaths.

These factors, they say, have caused morale to plummet and production to drop.

However, top department officials, including Chief Maurice T. Turner and the head of homicide, Capt. Jimmy Wilson, disagree with many of the rank and file detectives interviewed and say the lower rate today is the result of an increased number of murders involving people who did not know each other, such as those involved in robbery, drug and homosexual deaths. These are traditionally harder to solve than cases involving family members or friends, which generate more leads, they say.

Retired detective Jack Chaillet, one of the most respected members of the unit over the last two decades, echoed the views of other detectives interviewed:

"When you worked in homicide in the 1970s , you didn't have a sergeant or lieutenant leaning over your shoulder . . . How can they homicide management know what they're doing if they have never investigated deaths?"

Wilson denies that there is any morale problem in his unit. "We have now joined the police department," he said. "Before the branch was pretty much set apart from other units with a free hand to do pretty much what they wanted to do . . . I have enforced the rules and held them accountable for their work and their actions."

Wilson said that while he and his lieutenants, William Ritchie and Carl Alexander, have little experience investigating homicides, all three have extensive investigative experience in other units. He says the administrative skills that the three have are what is needed for homicide.

While some veteran detectives feel the crop of new investigators is too inexperienced, Wilson insists that the new investigators are among the best in the office. "What these guys lack in knowledge, they make up in enthusiasm," he said.

Wilson acknowledges that some detectives do not like the changes he has instituted, and concedes that he has found it necessary to transfer a few dissenters.

He took over the homicide unit in 1980 following a stormy shakeup where a number of detectives rebelled against the leadership of William C. Trussell, former chief of the Criminal Investigations Division (CID), which includes the burglary, robbery, sex, narcotics and homicide branches.

After Trussell left in late 1979, CID was turned over to Deputy Chief Alphonso Gibson, a former head of the internal affairs division. Wilson and other top homicide officials are also former internal affairs members.

Homicide detectives interviewed recently, who declined to be identified for fear of retribution, said that low morale has prompted a number of veteran homicide detectives to retire and that a number are now seeking transfers.

They said that the branch's ability to solve a high percentage of the city's homicides (approximately 200 a year) has resulted partly because they have excluded themselves from what they saw as more mundane police tasks to concentrate on their cases.

"In the old days you would get a call saying that your car needed to come in for an oil change and inspection," one detective said. "We would just ignore it, telling them we were working a case and didn't have time." Likewise, the detectives said, they attended to time-consuming paperwork and accounted for their hours at their discretion, rather than someone else's.

While Wilson says that the increase in attention to administrative details has had no negative effect on the closure rate, he said that the declining rate is nothing more than a mirror of the national trend.

According to the FBI's Uniform Crime Reporting Program, the national average for solving murders has dropped from an average in the early 1970s of about 80 percent to 72 percent in 1980, the last year for which there are complete figures.

Marvin Wolfgang, a specialist in criminology at the Wharton School of the University of Pennsylvania, concurs with Washington police officials. He attributes the decline in the closure rate nationally to the increase in the number of homicides involving strangers.

But veteran detectives insist that factor is at best marginal, and alone cannot account for the sharp decline in the D.C. branch's ability to solve murders.

In Baltimore, despite national trends, homicide detectives had a closure rate of 84 percent last year and 75 percent for the first six months this year. That city has about the same number of homicides as the district, and only 26 detectives to solve them compared to the 43 in the District of Columbia.

Washington's closure rate was 73 percent last year, compared to 64 percent for the first six months this year.