ATLANTA -- Brenda Muhammad stood in the front doorway, facing her oldest son's friend, who stared at her with eyes dulled from shock. "Bill, what's the matter with you?" she asked teasingly, knowing how the boy liked to cut up.

"Ms. Muhammad, it's Norbren," he sputtered. "{Somebody} just shot him."

The words tumbled around her like an avalanche, she recalled, squeezing out her breath as she felt the dam of control inside her crumble. "Oh, my God, no, no, no, no, please, not Norbren," she cried.

More than a year has passed since another juvenile blasted away part of her 16-year-old son's head in a dispute about Norbren's expensive athletic jacket. But the memory of that moment lingers in Muhammad's consciousness, a weighty presence tinging her happiest moments with a mother's indelible grief.

From that grief, however, has developed a determination to see good emerge. In December, Muhammad, 40, founded Mothers of Murdered Sons (MOMS), an organization designed to marshal forces against the senseless killing that plagues black communities. She and black leaders recently launched a nationwide campaign to end black-on-black violence.

"We're here to start the next movement," Muhammad told about 125 people at a rally outside Fulton County Courthouse. "This is a universal problem, and together we have to solve it."

In a charged atmosphere reminiscent of the 1960s civil rights movement, the Rev. Joseph Lowery, president of the Southern Christian Leadership Conference (SCLC), called for "a revival in the streets."

"The time has come to turn to one another instead of on one another," he said. "Unless we put an end to violence, it's going to put an end to us."

Atlanta police statistics show that, during the first nine months of last year, 86 percent of homicide victims and 86.3 percent of known perpetrators were black, with correspondingly similar figures in 1988 and 1989. Other large cities reported similar homicide patterns last year as the nation logged a record 23,220 murders, according to the federal Centers for Disease Control (CDC).

"It's a growing, serious problem, and it needs to be dealt with," said Fulton County Juvenile Court Judge Tom Dillon, noting that 16 juveniles were indicted for murder in 1990, nine in 1989 and three in 1988. "It's gotten worse . . . in the manner of the homicides. They've tended to be cold, calculated killings with automatic weapons rather than the result of emotional outbursts."

MOMS, the SCLC and other organizations plan to focus on causes of black-on-black violence. They said these are poverty, poor education and broken homes that sap youngsters' self-esteem and respect for others' rights and property, and a judicial system that responds sluggishly to -- and sentences lightly for -- black-on-black crime.

The 16-year-old charged as an adult in the shooting of Norbren Muhammad 14 months ago is free on bond awaiting trial.

Lowery criticized the county public defender's office, whose docket is so crowded that poor, black defendants are often jailed for months before seeing a lawyer and then are pressured to plea-bargain. Seeking a trial could mean several more months behind bars.

A recent study funded by the American Bar Association said Atlanta's public defender's office is "in worse shape than any other public defender's office we visited around the country."

"Black youth learn to disrespect the judicial system at an early age because it treats blacks like cattle and subhumans," Lowery said in an interview. "It says that black life isn't worth as much as white life, and it says that all the way to the electric chair."

Assistant County Attorney Joe Drolet said no statistics back Lowery's assertions and that prosecutors treat defendants equally.

Julius Debro, a criminal-justice professor at Clark Atlanta University who studied black-on-black homicide for the CDC, said he found that such killings account for about 80 percent of big-city murders, mostly between 10 p.m. and 1 a.m. on weekends.

The way the judicial system treats black-on-black crime is a "form of institutionalized racism," a holdover from a segregationist era when police sometimes waited more than a day to remove the body of a black from the street, Debro said. Such vestiges remain, he said, although a predominantly black power structure is in place here.

Debro, who has chaired the Metro Atlanta Crime Commission and served on several police department task forces, added: "It's been going on a long time, so when black officials get in, they tend to act the same way as white officials. . . . They act like all power brokers."

MOMS plans to monitor courts to see how much time elapses before cases go to trial and how blacks' sentences compare to those for similar crimes committed by whites.

But the most difficult work, Muhammad said, is planned in black communities. MOMS is forming surrogate-father and tutoring programs and support groups designed to bring parents together to "become more conscious of what's going on in our environment, so we can take better control."

The SCLC has started a program called "Liberation Lifestyles That Make Us Free at Last" to help combat the lure of the streets. Part of the solution, Lowery said, involves finding ways to provide better employment opportunities offering an economic alternative to the drug trade.

SCLC plans include sending people into streets, bars, pool halls and parks to revive a community spirit that, Lowery said, has waned since the heyday of the civil-rights movement.

"In the spirit of the church, we're gonna spread the word of nonviolence," Lowery said. "During the movement, the church was in the streets; then it went back in the chapel. We're taking it back to the streets."

Pulling together the black community is not easy, Muhammad said, citing a long history of mistrust that originated with plantation owners seeking to discourage black unity. Only "new lessons of human relations and love" can overcome this obstacle, she said. "Unity is a scary word in the black community. That trust factor has never really been there."

MOMS also plans a media campaign, said Muhammad, who owns an advertising and public-relations firm and has two other children. The group has set its sights on advertisers pushing expensive sneakers and jackets that poor youths often seek as status symbols, she said.

Such advertising slogans as "Just do it" that accompany the products, she said, provide a powerful subliminal message that, in a moment of anger, can lead a youth to commit regrettable acts.

MOMS also intends to spotlight Hollywood, where television shows and movies often undermine the image and morality of the black community, Muhammad said. The boy who shot her son, she said, was obsessed with the movie "Scarface." She said television conspicuously lacks shows about single mothers trying to raise children in troubled times.

"There is no support system from all these mediums while you're trying to teach your children right from wrong," Muhammad said. "The media is pulling them one way, the streets another, and you're just Mom. And the one thing they do know is that, whatever they do, Mom will be there right down to their dying bed in the intensive-care unit."

Muhammad said she has received queries about MOMS from parents and activists in the District, Boston, New York, Miami and Philadelphia. Detroit officials have asked her to address the City Council.

The only hope of halting the killing, she said, is a community-based, grass-roots movement in which blacks coalesce in a spirit of compassion and trust.

"I'm so tired of turning on the news every night and seeing another black body being covered up," Muhammad said. "If we can get black people together, we can get something going. But the first thing is to get us to unite and, hopefully, this will be the opportunity."