She heard her 18-year-old brother, identified as Tommie Cheatham, arguing with someone outside in the 800 block of West 101st Street at about 8:30 p.m.
When she went to walk her dog about 30 minutes later, she found him bleeding from multiple stab wounds. He died at the scene.
Cheatham was a freshman studying music at El Camino College. He was planning to transfer to the University of California, Los Angeles.
Cheatham had no known problems with law enforcement. Police do not believe the incident was gang related.
No suspect information was released.