A man is being questioned by Jersey Police on suspicion of indecent assault.
The 23 year old was arrested in the early hours of this morning.
Officers say a man in his twenties was allegedly indecently assaulted whilst on the dance-floor at the rear of Tanguys nightclub at around 12.40am.
They want to speak to anyone who saw what happened.
"Anyone in Tanguys last night who may have seen this or anyone with any information is asked to contact police on 612612 or the independent charity Crimestoppers anonymously on 0800 555 111 or via their Anonymous Online Form at Crimestoppers-uk.org"