When the noise from the party down the street turned to yelling and cursing, Phyllis Berry Myers decided it was time to go downstairs and turn on the alarm that protects her home in Northeast Washington.

Then the yelling stopped, and the gunfire began. Myers counted the pops — “one, two, three . . .” — until she got to 10. Seconds later, she heard the wail of police sirens.

Four houses away, a gunman had opened fire on a high school graduation barbecue, police said, wounding four people before speeding away in a dark-colored Acura shortly before 11 p.m. Wednesday.

The party was breaking up at the time of the shooting, a victim’s relative said. At least two people were shot in front of the house, in the 1200 block of 42nd Street NE; it wasn’t clear where the other shootings occurred. People scattered. Some raced inside through a back door; others spilled into the street. None of the injuries appeared serious, police said.

“I didn’t even look outside,” said Myers, a former administrator at a charter school once attended by the graduate being honored at the party. “I didn’t want to be in the line of fire.”

The attack on 42nd Street, in the Kenilworth-Parkside neighborhood, was part of a spasm of violence Wednesday night in the District.

The onslaught began about 8:25 p.m. with the fatal shooting of Dawon Markham, 42, in the 200 block of 62nd Street NE, near the Watts Branch playground and the Prince George’s County border.

Police said Markham, of Mitchellville, was found shot several times in the body and died at a hospital. Police had neither a description of the shooter nor a motive for the shooting.

Less than an hour after Markham was killed, a 17-year-old youth was fatally stabbed in the 4600 block of Hillside Road SE, police said. Police said the teenager, identified as Ernest Hart of Southeast, was pronounced dead at a hospital soon after.

Police said the youth was stabbed outside an apartment complex after a dispute that was not domestic in nature. On Thursday, crime scene technicians were back on the street, measuring the distance between chalk circles and marking small splotches of blood that ran nearly the length of a city block.

The shootings at the graduation party capped off the night of violence.

Police released few details of what occurred, but they said a gunman opened fire and hit four people: one in the foot, another in the stomach and hand, a third in the buttocks and the fourth in an arm.

Myers said the party was to celebrate the graduation of a girl from Luke Charles Moore Academy, an alternative high school in Northeast. Myers said the graduate and her sister, who has not finished high school, transferred to Luke Charles Moore last year from the Integrated Design and Electronics Academy (IDEA) Public Charter School.

Myers had worked at the charter school until she left last year to resume nonprofit work. She said that she knew the teen hosting the graduation party well and that the new graduate was also celebrating her recent enlistment in the Army.

Myers said she did not know who might have targeted the party, and police said they had made no arrest.

Two police officials said detectives were sorting through conflicting versions of the incident, including one in which the shooter became upset at the party and retrieved a gun from his car.

No one answered the door at the house Thursday.