(World Entertainment News Network) -- Brittany Murphy's widower Simon Monjack was in need of a heart bypass when he suffered a fatal cardiac arrest on Sunday night.

The actress' mother, Sharon, found Monjack unconscious in the master bedroom of the Hollywood Hills home he once shared with his late wife, and paramedics pronounced him dead at the scene.

Los Angeles police have launched an investigation into the 39-year-old Brit's passing, but officials announced on Monday there were "no signs of foul play or any criminal activity involved".

Medication prescribed to Monjack was found on the property but the Los Angeles County Assistant Chief Coroner Ed Winter has refused to comment on reports suggesting the writer suffered a drug overdose until results from toxicology tests are returned.

However, Monjack's spokesman, Roger Neal, doubts there is any truth to the overdose claims, because the Brit had been putting off heart surgery for some time.

Neal tells People.com, "I don't believe he had an overdose... Simon needed a (heart) bypass.

"I was told he needed a bypass, and I said to him, 'Simon, you have so much going on, let's keep you healthy.' I said, 'You want to be healthy. Don't you?' He said yes, but he said, 'The bypass can wait.' I don't know how much of an emergency it was. The doctors would have made him get it immediately if he needed it, but Sharon confirmed with me he did need a bypass.

"As far as empty (pill) bottles, I don't know anything about that. If you have a heart condition you're going to have prescription medication for yourself. You're going to be on some kind of medicine."

Neal insists Monjack never released details of his condition to the press because he didn't want the extra media attention the news would attract.

The rep adds, "They didn't make it public because he had so much going on."

"Clueless" star Murphy died at the same Hollywood Hills property in December. (

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