Latest: Troubled model Anna Nicole Smith died from pneumonia not a drug overdose, according to media reports in the US.

Preliminary findings reportedly reveal that tests performed during the autopsy on Smith show she had a severe case of pneumonia.

According to US publication The Enquirer, prescription drugs she had taken made the condition worse and played a role in her death.

Sources close to the death investigation claim the prescription drugs masked the seriousness of her pneumonia.

A full toxicology report has not yet been completed.

Smith had previously been hospitalised for pneumonia in the Bahamas after her son Daniel died in September (2006).