AceShowbiz - The mystery surrounding Brittany Murphy's widow Simon Monjack has just doubled after it emerged the producer and writer left a strange message on his own cell phone answer machine before he died last month.

Investigators found the eerie message, left on the day Monjack died, in his voicemail on his phone. In it, he says, "I need to go to the hospital. I have a fever." Later on in the recording, obtained by TMZ.com, Murphys' mother Sharon can be heard saying, "Tell them you have a fever." It's unclear who 'them' is.

The cause of Monjack's death has yet to be determined. Last week, Monjack's mother accused Sharon of ignoring her pleas to call a doctor in the hours before the filmmaker's death. Sharon Murphy found the director unconscious at the Hollywood Hills home he once shared with his late wife. Paramedics determined he had suffered a cardiac arrest and pronounced him dead at the scene.

Monjack's mother Linda claims she pleaded with his ex-mother-in-law to get Monjack medical help because she was so concerned about him on the night before he passed away. She told Britain's Daily Mail newspaper, "I'd pleaded with Sharon over and over during those last hours to get medical help, to get him to a hospital, but she didn't... I'd call and he wasn't even able to respond."

"It was at this point that I demanded to speak to Sharon, and I told her, 'Please, please call the doctor. Get him to hospital. Please just get him some help'. She told me that she'd 'been through this before' and that Simon was over the worse."

Sharon Murphy's publicist, Roger Neal, has slammed Monjack's accusations, insisting she did everything she could to help the filmmaker.