Pittsburgh Police from Zone 6 responded to 9-1-1 calls for reports of a person stabbed inside a residence in the 1300 block of Beechview Avenue just after 8:45 p.m.
Officers located a male victim with a stab wound under his arm. Medics transported him to the hospital in critical condition.
One female suspect was taken to police headquarters for questioning. Detectives from Major Crimes and the Crime Scene Unit were on scene.
The investigation is ongoing.