The Friday the 13th Murders season 1 episode 2 - How was the killer connected to the film The Exorcist?

The true-crime anthology series The Friday the 13th Murders, which was released on October 1, 2025, aired its second episode on October 8, 2025. Every episode of the six-part series revisits a shocking real-life murder that occurred on or around the infamous date of Friday the 13th.

Season 1, Episode 2 of The Friday the 13th Murders, titled We All Go a Little Mad, explores the brutal suicide-murder case of the Markle family that happened on November 16, 1987, and the surreal connection of the case to one of the most iconic horror films ever made, The Exorcist.

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The Friday the 13th Murders season 1 episode 2: The connection between the Markle suicide-murder and the 1973 horror movie, The Exorcist

The Friday the 13th Murders season 1 episode 2 explores the 1987 case of John Markle, a successful businessman who murdered his wife and two daughters in their Little Rock, Arkansas, home before taking his own life.

John Markle, his wife, and their two daughters moved to Little Rock in 1979 after Markle joined Stephens, Inc.. He soon rose through the ranks to become vice president in only about eight months due to his exceptional performance.

However, in October 1987, Markle had been sent on medical leave by Stephens while the accounts were being reviewed. This investigation led to the discovery of an extensive embezzlement scheme involving accounts belonging to his mother, which resulted in Markle being fired on November 13, 1987.

Days later, on November 16, 1987, John Markle murdered his wife and two daughters before taking his own life. The tragedy, which occurred just after Friday the 13th, shocked the community, and the case became even more unsettling when journalists uncovered who Markle’s mother was.

At the scene of the crime, investigators discovered a bloody Halloween mask and a letter written by John to his mother, Mercedes McCambridge, the Oscar-winning actress who famously voiced the demon Pazuzu in The Exorcist (1973).

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John's letter to his mother

The letter suggested that John Markle’s relationship with his mother was fraught with emotional distance and control. McCambridge, though a celebrated performer who was known for her strong personality, struggled with alcoholism. This affected the relationship between the mother and son.

John's letter made clear that McCambridge had no knowledge of his business dealings. However, it detailed a long list of bitter grievances that John had towards her growing up.

Mercedes McCambridge at the best advertising painting award, 1956 (Image via Getty)

Mercedes McCambridge did not comment publicly about the incident and the letter. However, she, Stephens Inc., and many of Markle’s former account holders became embroiled in litigation around the case, which dragged on into the 1990s.

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What is The Friday the 13th Murders all about?

Created by investigative journalist Lydia Crane, The Friday the 13th Murders weaves archival footage, police reports, interviews, and cinematic reenactments together into a haunting narrative to bring to viewers chilling true-crime stories that happened on or around Friday the 13th.

Rather than merely recounting crimes in a documentary fashion, the show often uses the date of the murder as a significant turning point in the story, presenting viewers with both factual stories and an eerie atmosphere.

The Friday the 13th Murders season 1 episode 2 stars David Cubitt as John Markle, and Mare Winningham as Markle’s wife, Christine. Ann Dowd appears briefly as Mercedes McCambridge, John’s mother.

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Catch The Friday the 13th Murders on Investigation Discovery.