An investigation has been launched after a 48-year-old man suffered a dislocated shoulder while being detained at a Leeds police station.
The Independent Police Complaints Commission has confirmed it is investigating an allegation of use of excessive force against West Yorkshire Police.
The incident is alleged to have taken place at Leeds Bridewell custody suite on December 7 last year (2009).
An IPCC spokesman said the incident was not brought to their attention or West Yorkshire Police's professional standards department until the man's solicitors lodged a complaint almost a year later on December 2 this year (2010).
The complaint was referred to the IPCC by West Yorkshire Police. The force confirmed they were assisting the enquiry but could not comment further at this stage.