"We're not sure if it is natural causes or a possible accident maybe because of the prescription medication found there," coroner tells PEOPLE
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Just before he died, Simon Monjack was making plans for a European getaway and a new book project.

Speaking to PEOPLE on May 14, just nine days before his death at age 40, the onetime screenwriter said he hoped to travel to Europe with Sharon Murphy, the mother of his late wife Brittany.

“Of course I ll take her with me – I can t leave her, ” he said of Sharon. Planning to begin work on a photography book about ballet, he said he hoped the project would be therapeutic given Brittany s love of ballet. “It seems fitting to do it,” he said.

A friend of Sharon’s confirms that it was she who found Monjack dead in the Hollywood home where the pair continued living after Brittany’s death. Already fragile in the wake of her daughter’s death five months earlier, a devastated Sharon is “not well at all,” says the friend.

“Brittany’s mom made the 911 call. He was unresponsive when responders arrived and was pronounced dead at the house,” L.A. Assistant Chief Coroner Ed Winter tells PEOPLE. “It’s being reported [by the responding fire department] as a possible heart attack. We’re not sure if it is natural causes or a possible accident maybe because of the prescription medication found there.”

Late last month, Sharon spoke to PEOPLE to vehemently refute rumors that she and Monjack were romantically involved.

“That’s disgusting,” she said. “We’re close friends and we’re family. It’s an awful and ridiculous thing to say.”

A History of Health Problems

Still, the British-born Monjack was no stranger to controversy. During his three-year marriage to Murphy he drew fire from critics who said he was controlling of her. The scrutiny only intensified after her death at age 32 in December from pneumonia, a low-blood count and multiple drug intoxication.

“Every story needs a villain,” he told PEOPLE. “I don’t understand why people say such horrible things.”

Monjack s own health had long been fraught with problems – and mystery. In January, Monjack’s mother, Linda Monjack, told PEOPLE that her son was “unwell” and that he had suffered “a slight heart attack” a week before Brittany s death.

LAPD spokeswoman Mary Grady says there was no sign of foul play surrounding Monjack’s death but that a coroner’s investigation is underway. “There were some prescription meds found,” she says. “I don’t know if they were involved. They will have to do an autopsy and toxicology report.”

In February, Monjack told PEOPLE that he had survived a battle with oral cancer. (Something Linda had claimed she had no knowledge of.) He also noted that an anti-seizure medication found at the house at the time of Brittany’s death was intended for his use but did not elaborate.

Having gone up and down on the scale frequently over the years, Monjack had packed on weight since his wife s death and struggled to regain his footing.

“Some days he wants to kill himself and other days, he seems to be coping better,” Linda Monjack said in January, noting that her son s closeness with his mother-in-law was helping them both to heal. “I think they are really clinging to each other for support.”