A 35-year-old man was shot to death early yesterday in a Capitol Hill row house during an incident that included an attempted sexual assault on his elderly landlady and a brief standoff between police officers and a man who barricaded himself on the upper floor of the house, D.C. police reported.

The body of the slain man was discovered after his younger brother surrendered about 6:30 a.m. to officers who had gone to the house in the 600 block of Acker Street NE to investigate a report of a disturbance, police said.

The woman, 74, was not injured.

Police identified the slain man as Marvin Clemons. He was found in a third-floor bedroom with a gunshot wound to his upper body and was pronounced dead at the scene by the D.C. medical examiner, police said.

Maurice Clemons, 29, was charged with second-degree murder and was taken to D.C. General Hospital after his arrest because police believed he might have been under the influence of drugs, according to police spokesman Sgt. Joseph Gentile.

Maurice Clemons "was acting in a irrational and violent manner," Gentile said. He was still being held at the hospital last night.

Gentile said investigators have not determined the circumstances that led to the shooting.

The owner of the house told a reporter yesterday that she was awakened about 5:45 a.m. by the sound of loud footsteps and that she went upstairs to investigate.

She said she was confronted by a man who threatened her and made lewd remarks before she was grabbed and attempts were made to remove her clothing.

"I started fighting him . . . . I told him I was going to call the police and he stopped. I tried to call Marvin [Clemons], but he didn't answer," the woman said.

When police arrived, the man was on an upper floor and refused to obey the commands of two officers armed with shotguns who ordered him to surrender.

"He was arguing with the policemen. He said to the police that 'My brother is already dead,' " the woman said. The man surrendered a short time later.

Dorothy White, who lives next door to the woman said she was working in her house about 6 a.m. when she heard a disturbance.

"I heard a scuffle. Then I heard a shot, pow!" White said. "I went . . . to see what was going on, then I heard someone hollering for a long time and then it stopped. I thought whoever it was must be on drugs because he was hollering like a madman."

A short time later, several residents of the one-block street said, about 50 heavily armed officers surrounded the house and blocked the street to traffic.

"Police were walking down the street with guns. I did not know what was going on," said Henrietta Johnson, who lives across the street. "I was scared to go outside."

The woman who owns the house where the slain man lived said he had rented an upper floor for about 18 months. During that time, she said, their relationship had been close and she had considered adopting him as her nephew.

She said she shared Marvin Clemons' excitement when his younger brother decided to move in about six months ago.

"I don't know what happened," she said. "They were very close."