NEW YORK (CBSNewYork) — A Bronx woman is dead, and her 9-year-old granddaughter seriously injured, after police said the woman’s live-in boyfriend went on a stabbing rampage inside their apartment.

He allegedly then then set the apartment on fire.

It happened around 5 a.m. Wednesday at the St. Mary Houses on East 156th Street.

Resident Loretta Fleming said she got a frantic knock on her door by the girl, a family friend who lives on the floor below, desperately needing help.

“She had a stab wound on her shoulder and she was bleeding down her leg,” Fleming said.

The girl was pleading to Fleming to keep her away from the man she calls “grandpa,” 1010 WINS’ Glenn Schuck reported.

“She said, My grandfather went crazy, please help me,’ and I said, ‘OK, I’m going to call 911,'” Fleming said. “She’s like, ‘Oh my God, he’s gonna come up here, he’s gonna get me.’ I said, ‘Heaven, he’s not gonna get you, you’re safe here.'”

When police arrived, they saw smoke coming from the girl’s eighth floor apartment. Inside, they found 55-year-old Henry Maldonado with a knife in his hand after the fire was extinguished, CBS2’s Ilana Gold reported.

“They give him orders to drop the knife,” said NYPD Deputy Chief Jason Wilcox. “He doesn’t comply, at which time the Emergency Services Unit deploys an electronic taser to subdue the male.”

Once they took Maldonado into custody, police said they found the girl’s grandmother, 60-year-old Carmen Irizarry, dead from multiple stab wounds.

Investigators said Maldonado woke both of them up and started attacking.

The girl had been stabbed during the altercation, but managed to flee the apartment, police said. She was taken to the hospital in stable condition.

Maldonado also had stab wounds to the arm and torso, police said. He was taken to the hospital in critical condition.

Police said the family of three lived in the apartment together. They said the grandmother was raising her granddaughter and that she and Maldonado had a history of domestic violence.

The investigation brought Police Commissioner Bill Bratton to the scene, where neighbors were devastated.

“She’s a great lady. The other day, she came to me about an application — she wanted to move and take her granddaughter away from here,” one woman said.

Police said charges against Maldonado are pending.

The investigation is ongoing.