Today, coroners in England and Wales investigate violent and unnatural deaths or sudden deaths where the cause is unknown. However, an inquest is not necessary if a sudden death was due to natural causes; instead the coroner may order a post-mortem examination to determine the cause of death. The coroner must hold an inquest if the person died a violent or unnatural death or died in prison or in other specified circumstances. It is the duty of the coroner's court to establish how, when and where the person died. A coroner may sit alone or, in certain circumstances, with a jury. If the coroner has reason to suspect murder, suicide, manslaughter or infanticide, or that the death was caused by a road accident, he or she must summon a jury.