Brittany Murphy had taken prescription medication and was experiencing flu-like symptoms before her death, and her mother reported the actress also had suffered from diabetes, a coroner spokesman toldPEOPLE.
An autopsy on the Clueless star, who suffered a heart attack and died Sunday morning at age 32, was underway Monday. A toxicology test for the presence of drugs and alcohol also will be conducted.
The Los Angeles Police Department has finished its initial probe of Murphy's death, concluding there were no signs that a crime occurred.
TMZ reported that Murphy began vomiting early on Sunday morning and told family members she felt very ill. She collapsed in the bathroom of her home soon afterwards.
While a Los Angeles County Coroner's official said Murphy appeared to have died of natural causes at the Hollywood Hills home she shared with her husband of two years, British screenwriter Simon Monjack, claims that a number of prescriptions for Murphy were found in her West Hollywood home have surfaced.
Speculation and reports that the actress died from anorexia or drug overdose are saturating the internet, but Murphy's cause of death is still unknown and it will take several weeks for the autopsy results.
However, friends of the actress say she "definitely had a drug problem" amid fears she may have died from taking the same prescription drugs as Michael Jackson.
Some friends claimed she was reportedly hooked on prescription drugs, including Vicodin, after a series of plastic surgery operations made her dependent on painkillers.
"We have been very worried something like this was about to happen," a friend told The Sun. "Brittany has been living life on the edge. She definitely had a drug problem and we have all begged her to seek help. Sadly our words fell on deaf ears."
Murphy's father, Angelo Bertolotti, who divorced Murphy's mother Sharon when the actress was young, said he had not seen her in the past few years and learned of her death through his son, "She was just an absolute doll since she was born," Bertolotti said from his Florida home. "Her personality was always outward. Everybody loved her - people that made movies with her, people on a cruise - they all loved her. She was just a regular gal."
Ashton Kutcher, who dated Murphy and starred alongside in Just Married, expressed his sadness Sunday to his 4 million twitter followers with the following message: "2day the world lost a little piece of sunshine. My deepest condolences go out 2 Brittany's family, her husband, & her amazing mother Sharon. See you on the other side kid."
Singer Jessica Simpson tweeted: "Brittany Murphy was an incredible ray of Light to so many people. Her smile was contagious. My prayers are with her family and loved ones."
Reality star Kim Kardashian tweeted: "I am in shock that Britney Murphy has died! Clueless is my all time favorite movie. My prayers go out to her family & husband."
Limp Bizkit singer Fred Durst tweeted: "RIP Brittany Murphy. What a sweet human being. My prayers are with her friends and family."
In addition to her stunning turn as a suicidal incest victim in Girl Interrupted Murphy played lesbian in the critically acclaimed HBO movie Common Ground and in The Dead Girl.
