Nearly four months after the shooting deaths of 32 people at Virginia Tech, investigators still have not determined a motive for the gunman, Seung Hui Cho, who also killed himself. But it is possible that Mr. Cho practiced the shootings in a classroom building in the days leading up to the April 16 massacre, according to the Richmond Times-Dispatch.

Witnesses have told the police that a man in a hooded sweatshirt was seen in Norris Hall on April 14, and investigators that day found the doors chained shut. Mr. Cho chained the doors shut two days later before killing 29 students and faculty members there, and then turning the gun on himself. He earlier killed two students in a dormitory.

Police officers who have been investigating the shootings held a news conference this morning in Blacksburg, Va., to provide updates on their work as the campus of Virginia Tech prepares for the fall term. Classes begin on Monday, August 20.

Besides the new witness statements that the gunman may have practiced, the police released few new details. They are still looking for Mr. Cho’s cellphone and the hard drive of his computer. They suspect that those devices might provide clues to why and how he chose his targets.

An eight-member state panel investigating the shootings is expected to release its findings later this month. —Martin Van Der Werf