"This death could've been preventable," Assistant Chief Ed Winter tells PEOPLE. "Murphy was planning on seeing a doctor, but she unfortunately passed away before she did. This was a case of a person with pneumonia who was anemic (having a low blood count) who was taking medication when she should've been getting medical treatment."
Chief Coroner Investigator Craig Harvey specified that pneumonia was the primary cause of death, with drugs and anemia as contributing factors.
Winter confirms that no illegal drugs were found in the actress's system: "It was only prescription and over-the-counter meds," he said.
In an interview with PEOPLE last month Murphy’s husband Simon Monjack maintained that his wife had visited a doctor. "I took very good care of my wife … She was on an antibiotic and she was taking cough medicine and doing all the right things," he said.
Winter tells PEOPLE that Murphy "had been sick for several days, and the last time she saw a doctor was awhile ago."
He added, "Her husband and mom had been sick for a few days, and they were getting over it when [Murphy] got it."
Regarding concern from Murphy's friends that Monjack should be investigated, Winter said: "He was never considered a suspect. No one's criminally liable here because this has been ruled an accident."