Nick Gargan was appointed as chief constable of Avon and Somerset Police in March last year.
Mr Gargan started his career with Leicestershire Constabulary in 1988 after completing a degree in French and politics at the University of Leicester.
He worked extensively on the investigation into the death of Diana, Princess of Wales.
A spokesman for the force said: "The matter has been referred to the IPCC by the Police and Crime Commissioner. It is not appropriate for us to comment any further."
More top news
A main road in Birmingham is set to remain closed for the entirety of Sunday due to a "very serious" crash.
It will be a frosty start for many across the UK with slow-clearing mist and fog across parts of central and southeastern England.
The prime minister says she has proven the "doubters" wrong but still faces opposition from both sides of the Brexit line.