Six people were killed and four others -- including a D.C. police officer -- were wounded Tuesday night and early yesterday in the District and Prince George's County, a spate of unusual violence that increased already high homicide totals in both jurisdictions.

The attacks began about 9:30 p.m. Tuesday and ended just before dawn yesterday, covering a stretch from Takoma in Northwest Washington to Capitol Heights in Maryland. Police said the incidents apparently were unrelated. Those killed included a man who remains unidentified, a Ballou High School senior, two 20-year-old women, and a 56-year-old man and his 22-year-old nephew.

As of yesterday, police had made an arrest in only one case: a Marine Corps sergeant who police said fatally shot the 56-year-old and the 22-year-old and wounded a woman -- all relatives of his estranged wife -- in Capitol Heights on Tuesday night.

Police in Prince George's and the District said they had not seen such a bloody night in some time. But both jurisdictions have seen homicide totals climb this year. In Prince George's, there already have been more killings this year -- 123 -- than in all of last year.

Yesterday, D.C. Mayor Anthony A. Williams (D) said the police department's homicide closure rate, about 48 percent, "is a cause of concern." The city has had 221 homicides this year, compared with 197 at the same time last year.

The first three fatal shootings occurred in less than an hour, and all in the District.

About 9:30 p.m. Tuesday, two women were killed and two men were seriously wounded when someone opened fire on their van, parked in the 4800 block of Alabama Avenue SE, police said. Killed were Latosha Graham and Tonya Thompson, both 20, of Southeast Washington.

Graham's mother, Christine Graham, said she heard the gunshots, about a block from her house. Soon after that, a friend called to say her daughter had been shot.

"I went to see her and hold her," Christine Graham said. "I held her until the cops came."

At 10 p.m., police found Mikel Queen, 17, the Ballou student, with numerous gunshot wounds in the parking lot of a small shopping center in the 4100 block of Wheeler Road SE. Police said that this area, known in the 1990s for near-constant gunfire, had not had a fatal shooting in months.

Queen lived on a nearby block of Eighth Street SE. His mother, Brenda Queen, said Mikel, whom the family called Mike, was the oldest of two children and enjoyed basketball. "He thought he could be the next Michael Jordan," she said.

While police were investigating the slayings, another victim was found. About 10:10 p.m., an unidentified man was found fatally shot next to a sidewalk in the 6600 block of Sandy Spring Road NW.

Ramsey said the man might have been killed elsewhere and his body dumped on the quiet side street along Metro tracks in the Takoma neighborhood.

In Prince George's, the trouble began shortly before midnight, police said.

That was when Marine Corps Sgt. Estabon Eugene Jr. arrived at a single-story detached house in the 1200 block of Capitol Heights Boulevard, just over the D.C. border, and screamed for his 22-year-old wife, they said. Eugene was facing a court appearance yesterday morning on charges that he had abused her, court documents said.

Eugene, 24, ran into the home with a 9mm pistol and fired first at Kelvin Chang, 56, his wife's uncle, according to police. Chang was struck several times, police said. Eugene next allegedly shot Chang's 49-year-old wife, seriously wounding her.

Then, police said, Eugene shot his wife's 22-year-old nephew, Aldwin Kelvin Chang. Both Kelvin and Aldwin Chang were killed.

Eugene then drove to the Mitchellville house of another relative, police said. He tried to break into the house through a rear door but fled after several people in the house woke up, said Cpl. Diane Richardson, a police spokeswoman.

Several hours later, Eugene drove past police headquarters in Palmer Park. A patrol officer recognized the gray Nissan Maxima that authorities said Eugene was driving and tried to stop him, Richardson said, but Eugene allegedly fled.

The officer chased Eugene onto the Capital Beltway and followed him until he veered off and struck a tree near the exit for Route 4, Richardson said. As officers approached Eugene's car, they heard a gunshot. They found him shot in the head, they said. He was hospitalized in critical condition and was on life support last night, police said.

The final shooting of the night happened about 4:40 a.m., when a man fired at Matthew Adcock, a D.C. police officer, during a chase near the Fort Totten Metro station in Northeast Washington. Adcock was grazed in the left forearm but continued to chase the man, said Sgt. Joe Gentile, a D.C. police spokesman. He said the man ran into nearby woods and got away.

Staff writer David Nakamura contributed to this report.