Now, a manhunt is under way.
Authorities say the 48-year-old victim, identified as Patricia Parham-Hayward, was strangled inside the building on Madison Avenue, about a block away from City Hall, just after 10 p.m.
Police say Parham-Hayward knew the suspect and let him inside, but they do not believe he was an aquaintance of the 59-year-old victim who survived.
At some point, the suspect strangled Parham-Hayward, possibly using a tie or a piece of clothing, in a separate room in the top-floor apartment.
Police say the suspect exited the room and attacked the second woman, assaulting her until she passed out. When she woke up, she found her friend dead in the other room.
Her injuries were not life threatening, but she initially had trouble speaking with authorities due to marks on her neck. She has since given officers a detailed account of what she witnessed.
Authorities say there were no signs of sexual assault, sexual trauma or sexual activity at all prior to death.
Police do not know what transpired when the victim was in the room with the suspect, nor do they believe anything was taken from the house.
The suspect is identified as a tall, thin Hispanic man in his early 30s, approximately 6-foot-3, wearing a black shirt, blue jacket and jeans.
Anyone with information is asked to call police.