Why Was Lincoln Murdered?

Why did General Grant suddenly alter his plans and decide not to go to Ford's Theater on the evening of Lincoln's assassination? Who, during that same night, tampered with the telegraph wires leading out of Washington? Why was the President's bodyguard at the playhouse, guilty of the grossest negligence, not punished nor even questioned? Perhaps the most serious reproach against historical writers is not that they have left such questions unanswered, but that they have failed to ask them. M...