Police believe Copeland, 18, was the first victim of accused child killer Daniel St. Hubert.
Wade Wilson, 17, was charged with the stabbing death of Josais Masson, 18.
Residents said not enough was done to keep Richard Pearson, 49, off the streets.
Police said the injured man, Andrew Hardy, is not cooperating with investigators.
A 34-year-old man was stabbed twice in the abdomen and slashed in the face, the NYPD said.
The man was stabbed during a fight on Sutphin Boulevard Tuesday morning, sources said.
Another two people were hurt in the attack, police said.
A 14-year-old girl who was suspended from the Richard Green School was stabbed twice Monday, NYPD says.
Richard Pearson, 49, was charged with attempted murder in the attack on a cellphone accessory vendor.
Noel Estevez killed Timothy Crump outside Mount Hope school, police said.
Noel Estevez, 14, told police that classmate Timothy Crump, 14, attacked him.
Noel Estevez and the victim, Timothy Crump, had a long-running beef, according to sources.
A man stabbed two people, one fatally, inside his mother's Springfield Gardens home, police say.
Timothy Crump, 14, was stabbed to death by a teenager outside Joseph H. Wade Middle School, police said.
Andrew Ramirez, 21, was killed outside the apartment building where he lived, police said.
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