Showing The Vision by Dean Koontz

The killer standing, standing with the butcher's knife in one hand, standing in shadow, his face in shadow but turning now, turning very slowly so that she'll be able to see his face, turning as if he is looking for her... Mary Bergen is a clairvoyant, able to foresee murders that will happen in the near future, but unable to prevent them from taking place. And now she is up against a power that is stronger than her own, a power that is taking her over, a power that is trying to kill her before she can identify it...