The school did not notify students by e-mail of the first shootings until 9:26 a.m., said Matt Dixon, who lives in the dorm. Mr. Dixon did not receive the e-mail message until he returned from his 9:05 class. When he left for that class, he said, a resident adviser told him not to use the central stairs, so he left another way. On dry erase boards, advisers had written, “Stay in your rooms,” Mr. Dixon said
