Detectives investigating a sexual assault on board a train from Nottingham to Sheffield have released these images in connection.
At around 8.30pm on Sunday 12 April, a woman was subject to sexualised comments before being sexually assaulted by a man standing behind her on the service.
The man then left the train at Alfreton.
Detectives believe the man in the images may have information which could help their investigation.
Anyone who recognises him is asked to contact British Transport Police by texting 61016 or by calling 0800 40 50 40, quoting reference 689 of 12 April.
Information can also be given anonymously to Crimestoppers on 0800 555 111.





