The Concept of Dread

Stephen King uses the concept of telling what's going to happen to his characters (e.g., that they're gonna die) before the event actually happens. This is a bold move by an author. Risky, in that you alienate the reader automatically by telling them that their favorite character is gonna die, leaving them with no motivation to go on. I know this happens, because I saw it when my wife was reading The Time Traveler's Wife.
But it left me wondering, when King writes this way, does he know how he's gonna die, or does he just write it in, knowing no more than that fact, and setting himself up for something later.