A knife-wielding woman was arrested Tuesday after police said she attacked and threatened to kill her ex-boyfriend at the Westfield mall. According to police, Hayley Nicole Welcome, 22, of New Haven, went to the mall shortly before 7 p.m. and met her 19-year-old ex, who works at the mall. He agreed to go to his car to retrieve an item belonging to her. Outside the mall she became angry over the breakup and attacked him, punching him in the face and ripping a chain off his neck, then pulling out a knife and threatening to kill him. As the two struggled over the knife, witnesses flagged down a Trumbull police officer on patrol. The officer reported seeing Welcome screaming at the victim, and a bystander yelled \u201cShe has a knife.\u201d The victim told the officer that Welcome had thrown the knife away when she saw police approaching. She was arrested without incident. The victim showed the officer where there knife was and police recovered it. The victim had scratches in several places on his body, but declined medical attention, police said. Welcome was charged with carrying a dangerous weapon, third-degree assault, second-degree threatening and breach of peace. Bond was $10,000 for court April 12.