Two days before the Virginia Tech massacre, witnesses saw a suspicious man in a hooded sweat shirt and the doors of the building where Seung Hui Cho killed 30 people were chained shut, police said Friday. Cho chained the doors of Norris Hall before his rampage there, but investigators said they had no indication he was the person who had chained the exits the first time. "It would be speculation to suggest that he was practicing locking the doors," State Police Superintendent Col. Steve Flaherty said.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

ROANOKE, Va. (AP) - Virginia Tech shooter Seung Hui Cho might have made a practice run two days before the massacre, even chaining the doors to the building where he killed 30 people, police said Friday.

Witnesses saw a suspicious male in a hooded sweat shirt in Norris Hall on Saturday, April 14, and authorities found that the building's doors had been chained shut, police said.

Cho, a mentally disturbed student, chained all the exits from Norris Hall before killing 29 students and faculty members after fatally shooting two people in a dormitory April 16. He killed himself as police broke through the chains and stormed the hall.

(This version corrects that police have not said they think Cho rehearsed the massacre.)

Written By SUE LINDSEY and ZINIE CHEN SAMPSON