A police officer died from a gunshot wound to the chest, a post-mortem examination has found.
The 43-year-old constable, from the Metropolitan Police's Specialist Protection Command, which guards the Prime Minister and other high profile figures, was found at a residential address in Camden, north London.
His death is not being treated as suspicious and detectives are investigating whether a police gun was used.
Officers were called shortly after 4pm on Tuesday and forced entry to an address in King's Terrace.
The man had a gunshot injury and was pronounced dead at 4.45pm. His next of kin have been informed.
He was not under investigation as part of either the "plebgate" probe or the inquiries into alleged phone hacking and corrupt payments to public officials.
An inquest will be opened at St Pancras Coroner's Court, Scotland Yard said.