Her youngest son, Matt Shaw, 21, graduated from college in May and was heading to graduate school, following in the footsteps of his older siblings, who already had degrees or marriages that had mostly whisked them away from the persistent shootings in their neighborhood.

But a few hours after the fireworks of July 4, Matt Shaw was fatally shot two blocks from his mother's home. He was standing with a group of friends in front of the A.K. Houses when another young man fired into the crowd, hitting no one, then chased Mr. Shaw along Lexington Avenue and shot him in the back.

On Tuesday, instead of helping her youngest son shop for school supplies, Ms. Shaw-Leary, 60, was sitting in State Supreme Court in Manhattan watching the arraignment of the man charged with killing him.

"I just miss him so, so, so much, every day," Ms. Shaw-Leary said through tears outside the courtroom, surrounded by some of her other children.

Ms. Shaw-Leary said prosecutors had told her they believed her son was killed in a case of mistaken identity.

Khalid Rahman, 20, pleaded not guilty to murder and other charges on Tuesday. He has been held without bail on Rikers Island since his arrest on July 13 and faces 15 years to life in prison if convicted.

Mr. Brown "had a bright future ahead of him," Cyrus R. Vance Jr., the Manhattan district attorney, said in a statement. "Instead, he will be remembered as a tragic victim."

East Harlem has been particularly struck by gun violence. The corner where Mr. Shaw was hanging out with friends, at East 128th Street and Lexington Avenue, is the same corner where a 17-year-old girl, Cheyenne Baez, was killed by a stray bullet two years ago.

In May, Mr. Shaw graduated from Le Moyne College, in Syracuse, and was looking forward to pursuing a master's degree in economics this fall at the State University of New York at Albany, Ms. Shaw-Leary said.

His mother, always worried about the guns on the streets, urged him to spend the summer with his sister in Atlanta. But as the Fourth of July holiday approached, Matt grew bored at his sister's house and came home.

"I just don't like New York in the summer for children," Ms. Shaw-Leary said. "They have nothing to do, and everybody has a gun."

Ms. Shaw-Leary, who works in customer service for Marriott Hotels, said she had made a practice of asking her children what they were carrying in their pockets when they left their apartment, grilling them about where they were headed and enforcing a curfew even in their adult years.

She described all of her children — three other sons and three daughters, the oldest of whom are twin 40-year-olds — as ambitious. One is studying fashion; another, culinary arts. One is a fashion photographer; another has a degree in social work.

"You can't move out of my house until you have a degree, until you are fully prepared for the world," she said. "You can't even get married until you are fully prepared for the world."

She described Matt as kind and generous. She was working a night shift on July 4 and called him at her apartment just before midnight. He told her he might go back outside.

"I told him to be safe," she said, choking back a tear.

She said she hoped that more people and politicians from African-American neighborhoods would join leaders like Mayor Michael R. Bloomberg and Police Commissioner Raymond W. Kelly in their efforts to get guns off the streets.

"Our kids are black and they're the ones killing each other," she said.