Regrets with Unknown Actions

Shawn, now insane and angry. Drowning in regret. Why? He killed his love of his life, Rose. Yet, he doesn't know why. But he knows how. She was stabbed, by Shawn himself. He's sure he did it because his hand was covered with her blood the moment he saw her dead. Now, Shawn regrets killing her. However, the reason for her death remains unknown. He tries to forget her, but he can't. He then becomes haunted by Rose... Literally.