THE EXORCIST is a horrifying story about a young girl possessed by the devil, but did you know Linda Blair was actually in the presence of true evil while filming the William Friedkin classic?

It all happened three years later in New York. It was the late 70s, and six men were killed and dismembered. The bodies were wrapped up in plastic bags, and each was dumped in the Hudson River like trash.

Due to the condition of the bodies, police were unable to identify the victims. However, upon investigating the men’s clothing and identifying tattoos, authorities determined that the men were gay—and that a serial killer targeted them at popular gay clubs.

It wasn’t until the body of film critic Addison Verrill was discovered beaten and stabbed to death inside his New York apartment that police had a new lead in the case. The murderer was a man named Paul Bateson, a 30-something X-ray technician he met at a nightclub on September 14, 1977.

Bateson confessed to going home with Verrill that fateful night, having sex with him, and bashing his skull with a metal skillet before stabbing him. Bateson ransacked Verrill’s apartment, stole a credit card and some cash, and left the writer to die in the nude.

The killer was awaiting sentencing in Riker’s prison when he allegedly bragged about his crime—and many others. He explained how he picked up countless men at bars, killed them, chopped them up, and threw them in the Hudson—just for fun. As the case made the news, director William Friedkin recognized the killer’s face staring back at him in the newspaper.

The killer had appeared in THE EXORCIST.

It was a scene where Regan McNeill is having a carotid angiography to determine if she has any brain damage. The scene is frightening on its own, but it becomes even more menacing after the realization that there’s a killer in the room.

Friedkin filmed the scene at NYU Medical School with a real neuropsychiatric surgeon and his team. Bateson was the surgeon’s assistant who helped prepare the little girl for her procedure. Shocked by the discovery, the director called up Bateson’s lawyer to schedule an interview with him.

During their meeting, Friedkin asked Bateson if he did kill all the men, and Bateson—a raging alcoholic—could only remember killing Verrill. He described how he met the film critic at a popular nightclub, and detailed how he took the man’s life.

Friedkin explained, “Though Bateson worked with a brain surgeon, he himself was not a brain surgeon because the body bags all had little indications that they were from the NYU Medical Center and that’s how the police tracked him.”

The killer also told Friedkin that police offered him a deal to confess to the multiple murders for a shorter sentence. Bateson would eventually be released from prison early in 2004.

This dark coincidence partly inspired Friedkin to direct the crime thriller CRUSING, which starred Al Pacino as an undercover New York cop investigating a serial killer targeting gay men. Although Bateson is widely believed to be responsible for the unidentified bodies that washed up in the Hudson River, there was no solid evidence linking him to the crime. And even though he brutally murdered another man in cold blood, he walks as a free man on the streets of New York today.