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Halloween night in New York City, 1981: a photographer and his young girlfriend are fatally shot, execution-style, in their Chelsea apartment. There is no forced entry, there are no obvious suspects and there is no clear motive.

For more than four decades, the chilling double-murder of lovebirds Ronald Sisman, 39, and Elizabeth Platzman, 20, has remained a mystery. Any leads in the case have long since turned ice cold.

Still, the case remains open, haunted by rumors of cult involvement, a never-recovered murder weapon, and a claimed connection to the infamous “Son of Sam” serial killings.

Now, with the help of a retired NYPD cold-case unit sergeant, The Independent reviews the Sisman-Platzman slayings — and learns what could crack the case wide open.

A Halloween horror show

While New York’s streets were filled with trick-or-treaters celebrating Halloween on Oct. 31, 1981, police were called around 7:50 p.m. to a grisly scene inside an apartment building at 205–207 W. 22nd St. in Manhattan’s Chelsea neighborhood.

Inside, officers discovered Sisman and Platzman’s bloodied bodies. The couple had been brutally beaten and each was shot in the back of the head execution style.

Sisman was an up-and-coming photographer who operated two photography businesses out of his Chelsea apartment.