From Virginia Tech at 2:50 pm:

An official Virginia Tech announcement. . . .
The campus alert has been lifted. The university will hold a press briefing at 3:15 p.m. in front of Burruss Hall.

From earlier today:

Virginia Tech Police have released a composite sketch of the person who was reported to be carrying a weapon on campus.  As police continue to search buildings on campus, they urge students not to return until the all-clear is sounded.

Tech officials say the initial report came in shortly after 9:00 am and label it  “credible”, coming from three youths attending a summer camp. They said they saw a man holding what may be a handgun covered by a cloth or covering of some sort. That’s what led to this morning’s emergency alert and lockdown.

Police from several jurisdictions swarmed onto the campus, but there are no indications they have found anyone meeting the man’s description. As of 12:45 pm, university officials still urge everyone on campus to remain indoors.