The suspect is the girl's own mother, identified as Anne Carimbocas, who allegedly stabbed young Briani Davis four times in the neck and back with an 8-inch kitchen knife.
The attack happened inside a two-family home just after 10:30 a.m.
Neighbors say even first responders seemed shocked.
"I just saw all of them running to the house, and then one came out and said to the other EMT, hurry up, it's a baby, it's a baby," neighbor Lindsay Fortune said.
Police say the vicious assault only ended because a man inside the home intervened.
"He is slightly injured," NYPD Commissioner Ray Kelly said. "He's cut on the leg with a knife. He actually holds the woman in custody until the police arrive."
Appearing incoherent and moaning loudly, Carimbocus was driven away from the scene in a squad car. Later at the 105th Precinct, she reportedly tried to stab an officer with a pen. She had to be subdued before being taken to North Shore Long Island Jewish Hospital for evaluation.
Meanwhile, investigators confirmed that the mother and daughter did not live at the home. They were just visiting friends.
Detectives are still trying to figure out what would lead a mother to try to kill her own daughter.
Briani continues to recover at the hospital.
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