Calgary police have charged a woman with attempted murder for an "unprovoked attack" in a home in the southwest last month that has left a man fighting for his life.

A 32-year-old woman is due to appear in court Wednesday, following a three-week investigation that led to her arrest on Saturday.

Police say they were called to a multi-family residence in the 1600 block of 12th Avenue S.W. just after midnight on Dec. 17, after reports of loud noises coming from a suite above.

Upon arrival, police found a man in serious medical condition. He remains in hospital in life-threatening condition.

Two women at the residence were taken into custody for questioning.

"Investigators believe it was an unprovoked attack, however, a more specific motive is not yet known," police said in a release.