By the common law his powers and duties are both judicial and ministerial. In his ministerial capacity he is merely a substitute for the sheriff, as when the sheriff is a party.[511] His powers and duties thereunder it is not the present purpose to state and define. His judicial authority relates to inquiries into cases of sudden death, by a jury of inquest, _super visum corporis_, or, as it is more commonly defined, an inquisition, with the assistance of a jury, over the body of any person who may have come to a sudden or violent death, or who may have died in prison.[512] It is not necessary that the death should be both violent and sudden, and that both these circumstances must concur to give the coroner jurisdiction. It is sufficient to give the coroner jurisdiction if the death occurs from any violence done to a person by another, although such violence may not have terminated the life of a party suddenly, and it is still the duty of the coroner to hold an inquest.[513] Indeed the presumption is that he has acted in good faith and on sufficient cause.[514] And so when several persons have been suddenly killed by the same violent cause, under circumstances proper to be inquired of by a coroner’s inquest, it is proper and necessary for the coroner, acting in good faith, to hold a separate inquest over each body.[515] A coroner’s inquest is a judicial investigation. The coroner cannot delegate his authority to any one. Neither can he appoint a deputy under the common law. He must act in person as any other judicial officer; and it may safely be said that a coroner has no power to appoint a deputy coroner, except where special provision is made therefor by statute.[516] In England, a coroner’s court is a court of record, and it has accordingly been held that trespass cannot be maintained for turning a person out of a room where the coroner is about to take an inquisition.[517] But in this country, it may safely be said that a coroner’s court is not one of record, but of inferior jurisdiction.[518] The performance of the functions of a coroner are judicial in their character; so judicial that he is protected under the principles which protect judicial officers from responsibility in a civil action brought by a private person. His proceedings amount to entries concerning matters of public interest, made under the sanction of an official oath, and in compliance or presumed compliance of the law.[519]