In what is undoubtedly the craziest story you’ll hear all summer, a Cape Cod murder that’s gone unsolved for over 40 years is the subject of a wild-but-that-doesn’t-mean-untrue theory that was uncovered via an anniversary screening of the movie Jaws, by none other than the son of Stephen King.

The story goes: an extra in Steven Spielberg’s 1975 thriller about a giant killer shark off the shores of a fictional New England island looks a lot like the composite sketch of a woman who was murdered on Cape Cod the same summer Jaws filmed there. And this was all uncovered by horror scion Joe Hill at a repertory screening.

Let’s unpack this very New England urban legend, shall we? On July 26, 1974, the dead body of a woman was found in the sand dunes in Provincetown, Massachusetts, on the northern end of Cape Cod. The woman’s body was mutilated (her hands cut off) and decomposed for as many as two weeks, both of which conditions prevented police from identifying the body. Known as the Lady of the Dunes, it’s become one of the longest-running and most talked about unsolved murders in America. In 2010, a composite of the woman’s face was reconstructed using digital technology.

Enter, then, one Joe Hill. Born Joseph Hillstrom King, he’s the son of famed horror author Stephen King. Hill had learned of the Lady of the Dunes case after reading about it in a book of famously unsolved cold cases. (A book, by the way, called Skeleton Crew: How Amateur Sleuths are Solving America’s Coldest Cases. Stephen King aficionados will recognize “Skeleton Crew” as being the title of one of King’s earlier short-story collections.) In 2015, shortly after reading about the case, Hill attended a 40th anniversary screening of Steven Spielberg’s Jaws, a movie that was filmed on Martha’s Vineyard (an island off the south of Cape Cod) in the summer of 1974. In one scene that involved extras milling about, Hill spotted a woman who he thought looked exactly like the 2010 composite recreation of the Lady of the Dunes.

Hill’s theory, which he posted on a Tumblr back in 2015, was recently referenced on the podcast Inside Jaws, and the Washington Post reached out to Hill for comment.

“I felt I had seen ‘Lady of the Dunes,'” Hill said. “That her face had come up out of the crowd at me. It came and went in a moment, and there was no rewind button.”

Hill later revisited the film via digital copy and, after floating the idea to an FBI friend who didn’t shoot the theory down outright, went frame by frame until he found a shot of the extra he thinks could be the mystery murder victim.

“I’ve heard it said that everyone who was out on Cape Cod in the summer of 1974 appears in the movie Jaws,” Hill told the Post. “I’m sure that’s an exaggeration, but there’s a nugget of truth. People knew there were movie stars on Martha’s Vineyard. The possibility that a person would make a stop on the island and appear in the movie is not unreasonable.”

There are dozens of bizarre angles to this particular unsolved murder, from the Jaws connection to the fact that one of the biggest pieces of evidence in the case involves the woman’s “signature New York style of dentistry” on her crowned teeth. These are the kinds of details you’d find in … a horror story. On top of that, a fiction writer (one who grew up in the shadow of a successful father, no less) stumbling upon this random connection and then digging into it semi-obsessively and writing himself into a story about it is also the stuff of a horror story.

LEVELS UPON LEVELS, MAN.

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