Police named a suspect Monday in the fatal shooting of a woman boarding a Metrobus on Sunday evening. They said a warrant was issued for Javon S. Foster, 27, but sources later said they think that he had committed suicide in New York.

The sources, speaking on the condition of anonymity because Foster’s identity had not been confirmed, said police think a man who killed himself on Long Island was the same person sought on a charge of second-degree murder in the death of Selina Brown, 20.

Police were awaiting positive identification, the sources said.

Foster, a Southeast Washington resident, was Brown’s longtime boyfriend and the father of her 23-month-old daughter. But her family thought that he was abusive, and they had begged her to break up with him, to little avail.

Not even Brown’s stepfather, a longtime D.C. police officer, could persuade her.

But in February, Brown filed a petition in court seeking sole custody of her child. Family members said that signaled a breakup, which they think led to the shooting that killed Brown and injured her child.

“Selina was a very humble young girl,” said Naomi Ferguson, 70, the mother of Brown’s stepfather, Derrick Ferguson. “She was just taken off her feet by this young man.”

“What happened is so sad,” said Naomi Ferguson, who lives in the Bronx. She said her son, who joined the police force 16 years ago, “was very frustrated” at his inability to help his stepdaughter safely escape the relationship.

As D.C. police announced the arrest warrant for Brown on Monday afternoon and publicized Foster’s picture, Brown’s loved ones mourned their loss and worried about the young survivor: A wound that police initially called a graze is more serious, according to authorities and family members.

D.C. police Cmdr. George Kucik, head of the criminal investigation division, called the shooting a “horrific crime” but declined to describe the toddler’s wounds. Naomi Ferguson said that a bullet went through the crown of the child’s nose and that she will need reconstructive surgery.

The girl’s injuries did not appear to be life-threatening, police said.

The shooting occurred about 5:40 p.m. Sunday at a B2 Metrobus stop at 18th Street and Minnesota Avenue SE. Naomi Ferguson said that Brown, who lived in Northeast Washington, had been visiting a friend and was waiting for the bus home.

Police said Brown was holding her child in her arms and boarding the bus, possibly with one foot on the first step, when she was shot several times in the face. A woman who lives near the scene told The Washington Post that a man and woman had argued before the shooting; police did not provide details about that part of the incident.

Brown, holding her daughter, fell into the bus as the driver quickly drove about a block down Minnesota Avenue with her aboard, police said. On Monday, police praised the driver for getting his passengers to safety.

“It was heroic,” Deputy Metro Transit Police Chief Leslie Campbell said at a news conference Monday at police headquarters. “He got the bus out of harm’s way.”