This is an interesting in the latest MSNBC article:
Gunman sent package to NBC News
Rambling communication, videos mailed between shootings, network says
I haven't heard anyone else mention this:
"Police searched Chos dorm room Tuesday and recovered, among other items, a chain and a combination lock, according to documents filed Wednesday. The front doors of Norris Hall, the classroom building, had been chained shut from the inside during the shooting rampage.
Other items that were seized included a folding knife; two computers, a hard disk and other computer disks; documents, books, notebooks and other writings; a digital camera; compact disks; and two Dremel tools, which are rotating tools used for cutting, sanding and other applications.
In an affidavit seeking the search warrant, police found a bomb threat note directed at engineering school buildings near the victims in the classroom building. In the past three weeks, Virginia Tech had received two other bomb threats; investigators said they had not connected those to Cho."