Real life Horror

After starting researching and looking into horror films, i was intrigued by the horror films, which are based on true events. As there is nothing more scary when watching a film, knowing its true and it has happened. The ones i mainly found which were based on real events, were the ones with paranormal activities and ghosts. For example, the exorcism of emily rose, the conjuring and the exorcist. A lot of people have said to have had a paranormal experience and many people believe in ghosts, however having not had one myself I'm very skeptical.

Another film which i did not expect which drew from real life experiences was 'The Nightmare on Elm Street.' Not in the sense of a real life Freddie Krueger but it was inspired by an article in the LA times about a group of Cambodian immigrants all died while having nightmares.

Based on true events: 
Although i find the films on ghosts scary, im not always convinced as i think there's the 'do i believe in ghosts' aspect which makes me feel like its more fiction. However when i watch a horror film which is about a crazy man on the loose who attacks women, this scares more as i feel like this could be more of a reality than ghosts as i have never had anything to make me believe they are real. 
A film that is based on true events which is like this is ' Wolf Creek' Which is about two british women who go back packing around Australia but when there car breaks down they get kid napped and tortured. It is a mix of two hitch hiker killers.I think i find this more frightening because of how real it is and could be.