Adam Lanza apparently planned the Sandy Hook massacre by himself and left no evidence of why he killed 27 people at a Connecticut elementary school last year, according to a report released today. "Why did the shooter murder twenty-seven people, including twenty children?" wrote Danbury State's Attorney Stephen Sedensky in the report, which closed an 11-month police investigation. "Unfortunately, that question may never be answered conclusively." The report does say Lanza planned all his actions, including his suicide, and even wore ear buds during the assault, the Hartford Courant reports. Also from the report: