Skipton police are appealing to night-clubbers who were in Strata nightclub in Skipton on the night of Saturday 12 July 2014, into the early hours of Sunday morning, after a man was subjected to a serious sexual assault.
Officers particularly want to speak to a man who alerted door staff to an incident in a cubicle in the male toilets at around 3am on Sunday 13 July.
It is also believed that some people may have taken photos or video footage shortly afterwards.
Police are asking these people to contact them as a matter of urgency along with anyone else who has any information about the incident.
If you were in Strata nightclub in the early hours of Sunday and can assist the police investigation, please contact North Yorkshire Police on 101, select option 2 and ask for Harrogate CID.
If you wish to remain anonymous, you can pass information to Crimestoppers on 0800 555 111.
Please quote reference 12140115512 when passing on information about this incident.
A 19-year-old man has been arrested in connection with the incident and is currently on police bail while further enquiries are carried out.