Brittany Murphy’s final days are being explored in the upcoming HBO documentary, “What Happened, Brittany Murphy?”.

In an exclusive sneak peek at the docuseries, shared by People, filmmakers reveal the chilling details surrounding Murphy’s death and her relationship with her husband, Simon Monjack, 40, who also mysteriously died just five months after her from similar causes.

The series will feature interviews with Monjack’s mother, Linda, and brother, James, as well as his former fiancée Elizabeth Ragsdale.

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According to Ragsdale, Monjack had a shady past, in fact, shortly after they were engaged, Ragsdale became pregnant and Monjack insisted she give birth in New York City.

“When I got to my little studio in New York, I called him and he answered. I said, ‘Simon, I’ve made it to …’ and before I could get that sentence out, he hung up on me. He left me pregnant and abandoned,” Ragsdale says in the documentary, via People.

“He was a disturbed individual who was used to conning people and Brittany was one of his last victims,” says director Cynthia Hill of Monjack. “There was a pattern of behaviour that became very obvious the more research that we did.”

Murphy’s makeup artist is also featured in the doc, revealing that while working with the star on her final project, 2009’s “Something Wicked”, she noticed Murphy was not herself.

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“Her eyes were so sunken, and she just seemed so sad,” says Trista Jordan. “She wasn’t herself. She was in so much pain. She had Bambi legs and couldn’t stand up.”

In February 2010, L.A. County Coroner Asst. Chief Ed Winter concluded that Murphy’s death was the result of untreated pneumonia, combined with anaemia and drug intoxication from prescription and over-the-counter medications, including painkillers and cold medicine. Winter confirmed there were no illegal drugs were found in her system.

“Her death was was so bizarre and there are so many twists and turns,” “What Happened, Brittany Murphy?” executive producer Buddy Day said.

“What Happened, Brittany Murphy?” airs on HBO Max on Oct. 14.