A woman was shot to death early Saturday in the Avondale neighborhood on the Northwest Side.

At 1:35 a.m., officers found 23-year-old Nancy Michelle Arroyo lying inside an apartment hallway in the 3900 block of West Roscoe, Chicago police and the Cook County medical examiner’s office said. She had been shot once in her head and once in her upper torso.

Arroyo, who lived in the Lincoln Park neighborhood, was dead at the scene, authorities said.

Witnesses heard her arguing with someone before gunshots rang out, police said. Investigators learned that two males and a female were seen running from the scene.

Two shell casings were recovered, and no one was in custody, police said.

Area North detectives are investigating.