The Chicago Tribune reported that troubled 23-year-old Cho Seung-Hui, left the invective-filled note in his dorm room.

The note included a rambling list of grievances and ended with the words "Ismail Ax" in red ink on the inside of one of his arms.

Sources close to the newspaper claimed Cho had shown recent signs of odd behavior, including setting a fire in a dorm room and allegedly stalking some women.

Investigators believe Cho at some point had been taking medication for depression. They are examining Cho's computer for more evidence.

But neighbors of Cho said they did not recognize that description of the gunman.

 "He was very quiet, always by himself," neighbor Abdul Shash said of the gunman. Shash said the gunman spent a lot of his free time playing basketball, and wouldn't respond if someone greeted him.

Marshall Main, who lives across the street, said the family had lived in the townhouse for several years.