She was taken to Harlem Hospital, where she was pronounced dead on arrival, police said.
Brown's mother, Crystal, told the Daily News, the suspect was a woman with whom Brown had quarreled in the past.
Crystal Brown said that her daughter and the woman quarreled over Brown's ex-boyfriend the week before.
"[She] was angry at [Brown] because of a past boyfriend that she had," the mother told the Daily News. "She didn't want the boyfriend coming around the neighborhood. My daughter tried to avoid fighting her that night, but my daughter's friend ended up fighting her to defend my daughter."
According to the Post, residents who knew both women saw the fight escalate to a fist fight Tuesday morning, the residents said.
“[The suspect] and her friends got drunk and came over and bothered her [Olivia],” Larelle Walker, 48, told the Post. "Olivia beat her up and [the woman] left and came back [with a gun] and said 'What's up now, b---h?' and shot her in the stomach."
Tuesday morning's shooting comes just days after mayoral candidates visited Lincoln Houses tenants' apartments to raise awareness about the poor living conditions there.
The candidates spent the night in several tenants homes.
"A lack of repairs, and an environment of crime and murder are what the residents of Lincoln Houses are forced to live with every day," Rev. Al Sharpton, who organized the visit, said said in a statement Tuesday.
"I was attempting to show whoever may be the next mayor of New York City what some people in this city have to deal with on a daily basis. This homicide is a reminder of that," he added.
Police said that the investigation was ongoing.