The Los Angeles Coroner's Office has put extra security around the investigation into the death of Johnson and Johnson heiress Casey Johnson, RadarOnline.com has exclusively learned.
An autopsy could be performed as early as Tuesday on Johnson's body to determine the exact cause of death.
A senior official with the L.A. Coroner's Office tells us: "We first need to talk to her doctor, family and friends to establish a medical history. Information points in the direction that Johnson suffered from diabetes. Due to leaks to the media from the Coroner's office, we have put the Casey Johnson Coroner case number 90 on a security hold. That means only 3 people at the Coroner's office has access to the top-secret investigator's notes.
Johnson's lifeless body was found Monday afternoon in a West Hollywood home; police said Johnson suffered "an apparent natural death." She was 30 years old.