A man has died from head injuries after an incident with a stun gun at a cattle market, police have said.
Officers were called to Darlington's auction mart in Clifton Road by ambulance crew members attending the scene at around 9am.
The injured man, who was 45 and from Ingelby Barwick, Stockton, Teesside, died this evening after being treated at James Cook University Hospital, Middlesbrough, a Durham Police spokesman said.
The death has been referred to the coroner.
A spokesman said: "Police are not looking for anyone else in connection with this incident and a bolt gun, used to stun animals before slaughter, has been recovered from the scene."
Officials at the market closed the site and officers from the Health and Safety Executive were informed.