In the opening scene of “Sinister,” a wannabe chilling suspenser, a family of four stands beneath a tree in a suburban backyard, hoods hiding their faces and nooses around their necks. Then, out of the blue, an unseen figure cuts down a branch, and the family members are hoisted into the air in slow motion, kicking and struggling for air until they finally dangle silently.

Shot on grainy Super 8 film, the sequence is meant to be both ordinary and horrific, in the sense that a commonplace setting unexpectedly becomes a scary killing ground.

Co-writer C. Robert Cargill claims that the opening image, which was the inspiration for the script, first came to him in a nightmare, and indeed, the whole tale is meant to register as the worst nightmare a family can experience.

But, alas, almost every element of “Sinister” is familiar and second rate, a result of several factors.  First and foremost, the whole movie feels like a product of a committee, whose members include the producer of “Paranormal Activity,” the writer-director of “The Exorcism of Emily Rose,” who is also credited as co-writer of this déjà vu saga.

By now, over a decade after the seminal “The Blair Witch Project,” there have been so many Hollywood stories, based on a movie-within-a movie and the use of found footage as narrative devices that the novelty has worn off.

In “Sinister,” a variant of the above formulas, the protagonist is a writer, who, while researching the disappearance of a young girl after the grisly murder of her family, discovers some terrifying home movies.  Like the other lead characters in similar pictures, by doing so, he unwittingly opens a door into a nightmarish mystery.

World-premiering at the South By Southwest (SXSW)  Fest as a “super secret midnight screening, “Sinister,” which is released theatrically by Summit-Lionsgate, is likely to be dismissed by most serious critics and generate quick coin in its opening weekend.

The talented Ethan Hawke, who seems lost here, plays Ellison Oswald, a crime writer who ten years ago made his reputation with his best-selling account of a notorious murder. Restless and desperate to replicate the critical and financial success of his first book, he moves his loyal wife (Juliet Rylance), over-anxious son (Mark Hall D’Addario) and artistic daughter (Clare Foley) into a home where a suburban family had been brutally executed and a child disappeared. His great hope and ambition is not just to resolve the mystery but also find inspiration and new ideas in the crime scene.

Predictably, following the dictates of this subgenre, Ellison discovers a mysterious box containing Super 8 footage of the murders, alongside footage of other, equally gruesome homicides.

As Ellison—and we the viewers–watches the carnage unfold on film, he realizes what we have known all along, namely, that he has stumbled onto evidence  not just of a single murder but of a whole decade of killing spree.

Rather than doing the logical thing and go to the police and local authorities, Ellison keeps the movies to himself, hoping to publish another acclaimed book based on the crimes.

As Ellison pieces together the facts about the crimes and the murderer, unseen intruders and inexplicable goings-on disrupt his once peaceful household.

Slowly, too slowly for a bright man, Ellison begins to realize that his self-centered, self-aggrandizing ambition has endangered him and the safety of his family, placing them in the hands of a ruthlessly bloodthirsty adversary, who had marked all of them as his next victims.

A more skillful director than Scott Derrickson, who has helmed the serviceable “The Exorcism of Emily Rose,” but also the dreadful remake of “The Day the Earth Stood Still,” might have made a decent, B-level thriller, but Derrickson, perhaps he is also the co-writer here, slavishly follow the second (or third) rate) scenario. Only sporadically punctuated by scary or thrilling moments, “Sinister” is a weak, disappointing movie even as a routine genre item.