D.C. police have launched a special investigation into a possible link between last week's execution-like slaying of a Lorton inmate and six killings that have occurred in the city this year -- all of which they say are drug-related.

Capt. Charles E. Samarra, head of the homicide branch, said his detectives have received "new information" that may connect Friday's killing of inmate Douglas M. Boney with the six other murders.

The launching of the investigation is the first formal indication from law enforcement officials here that the killing of Boney, a convicted heroin dealer, and a spate of other drug-related deaths may be tied to a possible drug war in the Washington area.

"That is the word on the street," Samarra said of the possible link between the killings. "That is what we are looking at."

Samarra refused to say what new information had been gathered.

However, a high-ranking official in the department said Edward Ford Sharrieff, who has been charged with the first-degree murder of Boney, is a key figure in the investigation.

A sergeant and six detectives yesterday begin reviewing the six unsolved drug cases for similarities and possible links.

Samarra said all six deaths involved execution-style slayings in which the assailant "went there with the intent to kill the person."

The victim in each case was someone believed to be involved in narcotics, he said.

The six deaths are:

On Jan. 7, about 7:30 a.m., Earl Sylvester Matthews, 32, of 1200 North Capitol St. NW, was found in the rear of the Washington Highland School at Eighth and Yuma streets SE. He had been shot in the head.

On Jan. 16, Martin Garces Jr., 24, of 2009 Naylor Rd. SE, was shot in the abdomen by one of four men riding in a car in the 100 block of Elmira Street SE.

On Jan. 22, Shawn Better, 16, a Ballou High School student, was discovered in a parking lot in the 4500 block of South Capitol Street. He had been shot once in the head.

On April 20, Robert Blount, 27, of 415 G. St. NE, was fatally shot by a person in a passing car as he stood on the corner of Fifth and H Streets NE.

On May 15, Julius Kinard, 23, of 1630 Massachusetts Ave. SE, and Cornell Mathis, 22, of 1321 Southview Dr., Oxon Hill, were shot in the backs of their heads as they sat in a car in the parking lot of a Roy Rogers restaurant on Georgia Avenue NW near Howard University.

Samarra said he has assigned Sgt. Robert N. Crist to review the cases with the detectives who have been handling the homicides. He said those detectives have been taken off of the daily routine in the division and specifically assigned to concentrate on those cases.

Capt. Kris Coligan, head of the narcotics division, said his detectives are giving the homicide division any information they may develop on the drug-related homicides from their dealings in narcotics areas.

Coligan said he does not believe there is a full-blown drug war in the form of a turf fight taking place in the city. He said he believes the deaths have resulted from people shortchanging dealers, skimming off the top, or ripping off drugs from other dealers.

Other law enforcement officials said they believe the slaying of Boney may be part of a war over territory.

It is well known, they said, that there is a substantial drug operation at Lorton related to any of several competing drug rings on the streets of Washington.

Last Friday's predawn raid on a minimum security prison facility may have been designed as a show of force by persons seeking a bigger role in the prison drug operation, the officials said.

The nature of the killing -- three men barging into a dormitory and then shooting a victim -- is odd, law enforcement officials said, and may have been designed for special effect. It would have been easier, they said, to shoot Boney while he was out on work release or to have him killed by another inmate rather than risk entering even a minimum security facility.

Sharrieff, who according to Assistant U.S. Attorney Karen Tandy, shot Boney "at point-blank range," is a principal in the D.C. investigation.

He and his associates are mentioned by witnesses as having been seen nearby at several of the slayings, according to police.

Sharrieff, who has been arrested on an assortment of narcotics, arson and assault charges over the years, is well known to D.C. police, who describe him as a flamboyant person with a penchant for expensive cars.

When Sharrieff was arrested Friday, his 1980 Cadillac was recovered nearby. The Cadillac was registered to the Lorton address of Robert (Pappy) Gault, a former U.S. Olympic boxing coach and a $20,000-a-year job counselor employed by the D.C. Department of Corrections, according to law enforcement officials.

Gault said in an interview this week that the car was registered at his address without his knowledge. He said he knew both Sharrieff and Boney, whom he described as "a very dear friend -- like a son."

Gault said he could give no reason why the car driven by Sharrieff would have been listed to the house at Lorton where Gault lives.

In addition to Sharrieff, two other suspects, Germain P. Stoddard, 24, of 400 Upshur St. NW, and John Elbert Landon, 30, of 4407 Lions St. in Marlow Heights, were arrested in connection with Boney's death. Sharrieff, 32, and Landon are being held under $1 million bond and Stoddard is being held on $500,000 bond.

Law enforcement officials initially believed that four gunmen were involved in the raid in which Boney died. On Tuesday, however, an FBI official said there are conflicting reports from eyewitnesses, and only three persons may have taken part.