New York — The New York Police Department says officers responding to a call about a man acting erratically shot and killed him as he lunged with a knife.The shooting happened on Monday afternoon in Brooklyn. The man has been identified as 32-year-old Dwayne Jeune.Police say Jeune's mother called 911, saying he was acting erratically. When they arrived, she let them inside.Chief of Patrol Terence Monahan says Jeune lunged with a "large carving knife". One officer fired a stun gun, but he kept advancing.Police say a second officer shot Jeune in the chest. He died at the scene. Monahan says the shooting unfolded "in seconds".When the mother called 911, she said Jeune was not acting violently and had no weapons.Police say it's unclear when he picked up the knife.