Ex

A man was arrested Wednesday night in Queens in connection with the stabbing death of a 6-year-old Brooklyn boy, hours after investigators used forensic evidence to identify a suspect, a police official said.

News of the arrest came less than an hour after police officials publicly identified the suspect, Daniel St. Hubert, 27. He has a long arrest record, including assault, and was paroled on May 23, the chief of detectives, Robert Boyce, said.

Mayor Bill de Blasio, who cleared a packed schedule Wednesday night to appear at a news conference at Police Headquarters with Police Commissioner William J. Bratton just before 8 p.m., said no effort had been spared to ensure that the suspect was tracked down.

An official speaking on the condition of anonymity said earlier that a preliminary match had been made between DNA on the knife used to kill the boy and a profile in the New York State database. At the news conference, the police declined to detail the nature of the forensic evidence recovered.

For much of Wednesday afternoon, an arrest seemed imminent.

Chief Boyce said at a news conference earlier in the day that the 'case has picked up a lot of steam.' But by night, he returned to the podium at Police Headquarters to say that detectives had yet to locate the suspect and that no arrests had been made.

For days, the police had been canvassing for witnesses, circulating a sketch of a man said to be the suspect, and going over arrests made nearby, including those for trespassing in public housing, in search of any possible leads in the crime.

With the matching of DNA from the knife to a name in the state criminal database, the investigation shifted to finding that person.

But even with the name, the suspect could not immediately be located and the mayor and police commissioner asked for help from the public, which had already flooded the Police Department with tips.

Police said Mr. St. Hubert is only a suspect in the attack on the boy and a 7-year-old girl and was not at this time a suspect in the fatal stabbing of Tanaya Copeland two nights earlier. Ms. Copeland, 18, was attacked with a similar knife on a street several blocks from the housing project where the children were stabbed. The police have said her killing may be linked to the attack on the two children.

That killing, on May 30, has drawn increased attention since the attack on the children. Prince Joshua Avitto, 6, who was known as P.J., was killed and Mikayla Capers, 7, was critically wounded.

The children were set upon as they boarded an elevator in the Boulevard Houses in East New York, and the crime has set the community on edge and led to outraged calls by elected leaders for better security in the neighborhood. Only one of the 18 buildings in the complex has security cameras, delaying efforts to get an image of a suspect in the boy's killing.

On Tuesday, Mayor Bill de Blasio criticized the New York City Housing Authority, saying the agency moved too slowly to install cameras in housing projects, despite the fact that millions of dollars had been allocated by the city for that purpose.

With no video of the attack, a sketch of the man circulated widely in the neighborhood, staring out from lamp posts, parking signs and store windows.

Detectives scoured the area for any relevant videos and witnesses, going door to door in the vast housing project, where more than 3,300 residents live.

Detectives had also lifted fingerprints found inside the elevator where the children were attacked, hoping that the prints of the assailant were among the many prints inside. It was not immediately known if the suspect's prints turned up there.

But the main physical evidence in both murders are the kitchen knives the killer left behind. Outside the housing development, witnesses saw the fleeing man drop an eight-inch blade with 'Dura Edge by Imperial Knife' written on the side, the police said; that line of knives has not been manufactured since 2004. The same make of blade was left near Ms. Copeland's body, the police said.

In that case, there were no witnesses to the killing or the suspect's flight, only a grainy camera image of a man - of husky build and in clothes similar to those described in Sunday's attack - running from near the scene. A taxi driver found the body of Ms. Copeland, a popular teenager who played in a community marching band, on the street and called the police.

The longer the manhunt went unresolved, the more frayed nerves have become in the area of East New York.

At a news conference Wednesday morning, Borough President Eric Adams told residents to call police if they saw the suspect, not take the law into their own hands. He was echoed by Rochelle Copeland, the mother of Ms. Copeland. She also warned her neighbors to stay alert, and not walk around with their attention focused on their phones.

Overheard conversations among neighbors, around shaded benches, on street corners, and in delis, crackled with anger, and a want for revenge.

'If I see him, that's it, I only need less than a minute with him,' said a man.

'Do that to a child? The streets will tear him apart, and he'll deserve it,' said another.

The supermarket chain Western Beef announced on Wednesday they would give $50,000 for information leading to the conviction of the killer. This increased the pot of reward money to nearly $70,000.

Near where two uniformed officers kept up the police line in front of the building where P.J. was killed, the shrine to the boy continued to grow - with candles, stuffed toys, Spider Man balloons and a hand drawn portrait of the boy.