From TMZ:
We now know who made the call to 911 after Don Cornelius shot himself in the head early this morning — it was his own son.
Law enforcement sources tell TMZ … one of Don’s two sons made the call around 4:00 AM … and paramedics were immediately dispatched to Don’s Sherman Oaks home in an effort to save his life.
Don was transported to a nearby hospital — where he was later pronounced dead.
Cornelius was 75 years old.