Cal. Gov. Code § 27491.5

The cause of death appearing on a certificate of death signed by the coroner shall be in conformity with facts ascertained from inquiry, autopsy and other scientific findings. In case of death without medical attendance and without violence, casualty, criminal or undue means, the coroner may, without holding an inquest or autopsy, make the certificate of death from statements of relatives, persons last in attendance, or persons present at the time of death, after due medical consultation and opinion has been given by one qualified and licensed to practice medicine and so recorded in the records of the death, providing such information affords clear grounds to establish the correct medical cause of death within accepted medical practice and within the requirements for accuracy prescribed by the Division of Vital Statistics of the State Department of Health Services. The coroner shall not finally exclude crime, suicide, or accident as a cause of death because of lack of evidence.