The 52-year-old woman was killed in a fight inside an apartment on Bay Ridge Avenue in Bay Ridge just after 7 a.m.
Several people in the apartment building witnessed the attack and may have been injured, but not stabbed.
As police responded to a report of an emotionally disturbed person, a 42-year-old man emerged from the building and was placed into custody. Charges against the man are now pending.
Detectives are now sorting the case out, including the relation between victim and suspect.