Mount Vernon police Chief Barbara Duncan said that the girl's mother, a registered nurse, was at work when she called police at about 10:36 p.m. on Thursday to ask them to go to their house because she had been having an argument with her husband on the phone.
The nature of the argument was not disclosed.
As police officers arrived at the house, they heard a banging sound like a screen door being closed at the back of the house, and the woman's husband walked out and surrendered, the police chief said.
Inside the home, officers found the child and the 42-year-old woman in separate rooms on the second floor, Duncan said. The child, identified as Ayana Evans, had been shot in the torso; the baby sitter, Lorna Williams of Florida, was shot in the side of the head.
It was unclear whether the two victims had been shot before the girl's mother, identified as Joan Whitfield, 47, argued with her husband over the phone and called police, Duncan said.
Whitfield is an active member of a branch of the military who recently served in the Middle East. She recently moved with her daughter to Mount Vernon. It's unclear whether her husband, Darrell Evans, was living with them. His last known residence was Brooklyn.
Evans, 50, was expected to be arraigned on two counts of second-degree murder on Friday, the police chief said.
A handgun was recovered at the house and was submitted for analyses to determine whether it was used in the slayings.
The police chief said the mother arrived shortly after calling police and after her daughter had been taken to a Mount Vernon Hospital, where she was pronounced dead. Duncan said the sitter was dead at the scene.
Duncan said were investigating whether there was an order of protection against Evans. Police did not know of any divorce or separation proceedings underway.
Mount Vernon Mayor Clinton Young said that the slayings happened on his street, a tree-lined upper-middle-class neighborhood of neat private homes about 15 miles north of midtown Manhattan.
"My entire neighborhood is in shock," he said. "I remember seeing this little girl riding her bicycle and walking to school with her friends."
Of the girl's mother, he said, "She lost her child. It was an extremely emotional situation last evening."
Tobie Tripodi, who lives across the street and down a couple houses from where Thursday's shootings happened, said that she was awakened last night by the police activity. She said the girl and her family had recently moved in and "seemed like a quiet family."
She said she had waved to the child on her way to school.
"I'm horrified by it," Tripodi said of the killing. "A child? Come on. The most innocent among us."
