Fear X (2003) on Netflix

Plot summary

Harry Caine's pregnant wife, Claire, was shot dead beside a DEA agent at the shopping mall where he works as a security guard. His co-workers sympathize with him as he investigates the killing, though they grow concerned when he becomes aggressive with customers. He cannot sleep, troubled by visions of Claire walking toward an empty house in his neighborhood. The police question him and show him a blurry photograph of a man they call his wife's killer. A co-worker gives him security footage, and in it he watches the murder. Believing the empty house holds answers, he breaks in and finds film negatives on a bedroom floor. He develops them and sees they were taken in Morristown, Montana, a town he visited with Claire. He drives there and checks into the hotel where they stayed.