The Coroner's investigation is the process by which the Coroner establishes who has died, and how, when, and where they died. The Coroner may decide, as part of the investigation, to hold an inquest.
In some cases a death may be referred to the Police for investigation on behalf of a Coroner. This may be because the Police have expertise eg. relating to a road traffic collision or criminal activity may be relevant to the death.
In some cases other organisations such as a hospital, the Health & Safety Executive the Prisons and Probation Ombudsman, the Care Quality Commission or the Independent Police Complaints Commission are required to conduct a separate investigation into the death. This investigation usually takes place first and the Coroner will be given the results so he or she can user the information in the inquest.