The man who set fire to a Baltimore rowhouse, killing a family of seven last year, pleaded guilty in federal court yesterday and implored the relatives of his victims to grant him even a small measure of forgiveness.

"I will never, ever, as long as there is breath in my lungs, ever forgive myself," Darrell L. Brooks, 22, said, choking back tears.

Under the terms of a plea agreement, Brooks was sentenced to life in prison without parole on a charge of arson resulting in death. Prosecutors had considered seeking the death penalty but said they accepted the plea agreement after consulting with the victims' relatives and factoring in Brooks's "impaired" mental capacity.

"He's going to die in jail," said U.S. Attorney Thomas M. DiBiagio after the hearing. "He's got another 50 to 60 years to think about what he did every day he sits in that cell."

Brooks, a street-level drug dealer with a long criminal record, targeted the home directly across the street from his because the family there had repeatedly called police to report drug sales, prosecutors said.

Capping an emotional, hour-long hearing, Brooks turned to face more than a dozen relatives and friends of his victims, Angela Dawson, 36; her husband, Carnell Dawson Sr., 43; and Angela Dawson's daughter and four sons. The relatives sat in the front rows of the large courtroom.

"There is or never will be the right words to tell you how truly sorry I am," Brooks said. He initially read from a page of notes but discarded them almost immediately.

Brooks said that when he found out that prosecutors were considering the death penalty, he thought: "Great, now I can pay for my actions. I thought I deserved nothing but death."

Tears welling, Brooks said he felt that way even though he knew it would be difficult for his mother. His older brother was shot to death, defense attorneys said.

They also said Brooks was treated for mental health problems as a teenager.

Brooks said that if anyone harmed any of his relatives, he would want those responsible to pay with their lives. "This is not for sympathy," he continued. "This is to let you know how truly sorry I feel. I never meant to hurt nobody."

Referring to the children, ages 9 to 14, who perished in the fire, Brooks said: "I knew those kids; I loved them. I swear I didn't mean it, I swear."

The people in the nearly full courtroom sat in rapt silence as Brooks spoke. Some of the Dawson relatives appeared near tears. Earlier in the hearing, seven of them addressed U.S. District Judge Marvin J. Garbis, registering their sorrow and speaking of their struggle to heal. None spoke of retribution.

"I hope and pray that this does not happen to another family. I miss my family," Donnell Golden, mother of Angela Dawson, said to the judge. "I hope people just learn to love one another."

After the hearing, Golden said she doubted the sincerity of Brooks's apology.

The arson attack, which occurred about 2:20 a.m. Oct. 16, 2002, shocked a community saturated with crime and brought calls for change in the city's drug-fighting efforts as well as in the state's probation department, which failed to keep tabs on Brooks after previous arrests.

Angela Dawson and her five children were dead at the scene. Carnell Dawson Sr. fell from an upper floor of the rented rowhouse and died a week later from a skull fracture, burns and other injuries.

According to a statement of facts filed as part of the plea agreement, Baltimore police received at least 34 calls from the Dawson home reporting drug dealing in the neighborhood between June and October 2002.

Witnesses said Brooks said numerous times that he was angry at Angela Dawson for calling police. Two weeks before the fire, he told friends that he had thrown two Molotov cocktails -- beer bottles filled with gasoline and topped with a cloth wick -- through a rear kitchen window of the Dawson home. The kitchen was damaged, although the family escaped.

According to the document, a few hours before the fire, he quarreled with Angela Dawson and was heard saying: "You need to mind your own business. . . . You know what happens to snitches."

Later, Brooks kicked open the Dawsons' door, splashed gasoline on the floor, ignited it and ran away, according to the document. A few minutes later, Brooks returned to his third-floor bedroom, washed his hands, changed his clothes and tried to watch the fire from the front of his building but was told to get inside by a police officer, the document said.

Later that morning, when told that no one had survived, Brooks responded that Angela Dawson should not have called the police, according to the document.

Of the neighborhood where the Dawsons died, Baltimore Police Commissioner Kevin Clark said, "There's still drugs there, but it's not as blatant as it once was."

Clark said nearly three dozen community groups met last week to discuss how they could help police.

Darrell L. Brooks, in a 2002 police photo. Prosecutors decided against seeking the death penalty for him.The six victims who died at the scene of the fire: Angela Dawson, 36; LaWanda Dawson, 14; Juan Ortiz, 12; Kevin Dawson, 9; his twin, Keith; and Carnell Dawson Jr., 10. A week later, Carnell Dawson Sr., 43, died of his injuries. Angela Dawson had regularly called police about drug dealing in her neighborhood, prompting Brooks's attack.