Ellison's worth as a detective seems questionable. He spends lots of time writing down redundant questions ("Where is Stephanie?") and talking to himself.
Sinister is, in its way, it is a found-footage horror film, as the audience sees terrible acts committed in front of a movie camera within the movie. In this case, we see the footage as it's found: Ellison Oswalt (Ethan Hawke) moves his family into a new house and discovers a box full of eight-millimeter movies and a projector. As he sits down to watch, he's at first entertained by typical home-movie footage, then increasingly horrified -- by creepy, shocking images, including a scene showing a family hanging from a tree in his current backyard.
The movies' eight-millimeter grain and datedness provide at least part of the creepy effect. In this, Scott Derrickson's film recalls a couple of other movies that use the format as part of their plotting, J.J. Abrams' Super 8 (2011) and Joel Schumacher's 8MM (1999). Here the format is offered as the familiar means by which regular people documented their lives, and that familiarity leads directly to what Ellison comes to see as "sinister," that is, the extent of the documentation, the detail and quantity. A true crime writer, he has moved his family into this house knowing that its previous occupants were murdered. His first book, Kentucky Blood, was a massive nonfiction hit, and he's been trying to recapture that mojo since, much to the chagrin of his wife Tracy (Juliet Rylance). Now, though he's repulsed by his found footage, he also thinks he must be on to something; maybe he can crack a serial killing case.
Ellison's worth as a detective seems questionable. He spends lots of time writing down redundant questions ("Where is Stephanie?") and talking to himself, and so, talking the audience through the story. For actual data, he relies on other people's accounts. The movie establishes early on that cops tend to resent Ellison's books, which aim to correct what he presents as clumsy police work, and then wrings some nicely understated comic relief from the single, unnamed deputy (James Ransone) who likes Ellison's work and wants to help out with the investigation.
But even with the police and a local occult expert (an uncredited Vincent D'Onofrio) involved, that investigation often consists of Ellison walking around the house at night, trying to figure out the sources of various ambient noises. Other family members experience their own scary-movie symptoms: his son Trevor (Michael Hall D'Addario) has night terrors and his daughter Ashley (Clare Foley) paints some disturbing pictures.
What happens in Sinister, then, does not depart from any number of other haunted house pictures. But it makes effective use of the found footage, the eight millimeter segments serving as part of the mystery, what needs to be deciphered, instead of a gimmick. Around this footage, Derrickson offers other evocative images, polished long-take cinematography and clever blocking that create plenty of eerie empty space as Ellison wanders around in the dark. Derrickson knows how to ground his horror stories in, if not quite reality, at least other genres. The Exorcism of Emily Rose (2005) combines horror with courtroom drama; Sinister's genre-crossing is more meta, as a true-crime mystery gives way to supernatural chills -- Ellison fancies himself a modern Truman Capote but may turn out to be more like a Stephen King character.
Hawke, leading a pared-down cast, has that haunted look down pat, although after a certain point, Ellison's ranting defensiveness becomes repetitive. Like a lot of horror movies, Sinister does not present a feature's worth of story. Though Derrickson does an adequate job of stretching it out with atmosphere and character development, it ends up feeling like enough plot for a tight 90 minutes, but not quite the 110 it actually runs. Within this time, the central mystery barely develops. Ellison spends much of the movie scared and speculating, until at last someone else explains what's going on in the final stretch.
In this sense, the storytelling of Sinister resembles that of more typical found footage movies. The Blair Witch Project and Paranormal Activity depend more on mounting dread and recognizable characters than tightly crafted plot twists. Sinister lacks the visceral terror of those movies; it has unsettling imagery, a few cheaply effective jump scares, and committed performances, but nothing likely to burn into your brain. It's a passing shiver rather than a full-on haunting.