Six fatal shootings in 27 hours drove the number of homicides in the District to 201, one more than at this time last year.

The sudden rise in District homicides -- 13 so far in June and 18 since the beginning of the Memorial Day weekend -- wiped out what had been a slight decline this year from 1989's record-setting pace.

D.C. police officials had reacted with caution when the homicide rate showed a decrease from January to May, and yesterday they were careful about drawing conclusions from the new figures.

"I think a lot of homicides tend to come in spurts," said Capt. Alfred J. Broadbent, who has headed the homicide unit since February. "There appears to be no pattern."

Beginning just after midnight Sunday and ending at 2:48 a.m. Tuesday, police recorded six homicides. The victims ranged in age from 17 to 34.

One suspect has been arrested in connection with the shooting death of Mark Murphy, a 17-year-old Southeast youth who was found in the 2500 block of Sayles Place SE early yesterday.

The suspect, Anthony Payne, 22, has been charged with first-degree murder. Police said the shooting stemmed from an argument.

One of the homicides took place in a known drug area, but police said a motive has not been established.

About 55 percent of the District's homicides are drug-related this year, holding to a pattern set in 1989. And although all major statistics used to measure drug use in the District show a decline this year, one prime forecaster yesterday released results showing a slight increase for May.

Figures from the Pretrial Services Agency show the percentage of adults arrested on criminal charges who tested positive for drug use edged up to 56 percent in May, compared with 55 percent in April. That is still a significant drop since February 1988, when 76 percent of all adults arrested on criminal charges tested positive for some drug.

So far in 1990, investigators have solved about 60 percent of the homicides, a figure Broadbent said he would like to see raised. He said the public often can be a critical link in solving cases.

"We really need the help of the community," Broadbent said. "Very rarely does a murder occur without any witnesses."

The number of homicides committed by armed assailants has risen this year, continuing a trend that began in 1987.

In 1990, four out of five homicides -- 80 percent -- have involved the use of firearms, Broadbent said. The comparable figure in 1989 was 77 percent; in 1988, 72 percent; and in 1987, 62 percent.

Aside from that type of analysis, investigators tend not to go by the statistics of the moment because, as Broadbent said, "things even out in the end."

When the homicide rate declined for the first time in three years during the first quarter of this year, Police Chief Isaac Fulwood Jr. pointed out that a few violent weekends could reverse the trend.

As of May 1, there were 152 District homicides, compared with 165 for the same period last year.

In the recent spate, all six victims were gunned down on the street. Three of the victims were killed in Northeast, two in Southeast and one in Northwest.

The first shooting took place early Monday, just after midnight, in the 4900 block of Fort Totten Drive NE. The victim, Ron Coleman, 25, died from gunshot wounds at 12:31 a.m.

At 3:24 a.m., police found a 27-year-old man suffering from gunshot wounds in the 300 block of V Street NW. The victim, whose name has not been released pending notification of relatives, died at 9:14 a.m.

Bernard E. Johnson, 24, was found suffering from gunshot wounds about 5 p.m. in the 6200 block of Eastern Avenue NE. Johnson, of the 500 block of Nicholson Street NE, died at 7 p.m.

Police, meanwhile, were responding to the shooting of Timothy Lewis in the 4800 block of Benning Road SE. Lewis, 21, who lived on the same block, was pronounced dead by the Medical Examiner's Office at 8:25 p.m.

Police also are investigating the shooting death of Nathaniel Williams, 34. He was found at 14th Street and Duncan Place at 2:48 a.m. Tuesday suffering from multiple gunshot wounds. He was pronounced dead at 4 a.m.Staff writer Nancy Lewis contributed to this report.