A woman was fatally stabbed in Brooklyn during a domestic dispute — and her son was taken into custody as a person of interest in the homicide, police and sources said.

Neighbors who heard the victim’s screams and raced to the victim were able to nab her attacker and hold him until authorities arrived at 333 E. 92nd St. in East Flatbush.

The deadline incident unfolded around 11:40 p.m. when residents of the seven-story building heard the woman’s cries for help.

“I just heard a loud scream, a woman screaming, ‘Help me!’ ” said one resident, 28, who asked to remain anonymous. “After that, I heard a faint moan.”

Police responded to a 911 and found the victim with stab wounds throughout her body before taking her son into custody, according to authorities and sources.

The good Samaritan said he saw another man holding the stabber down, and rushed in to give assistance.

“I went straight for the knife,” he said. “It was a kitchen knife, a steak knife. The blade was seven or eight inches long…  I grabbed the blade. I held on to it. He tried to yank it away. It sliced my fingers.”

The victim has not been publicly identified and no arrests have been made.