A teenage boy has been sexually assaulted on a train travelling through Wiltshire.
Police detectives are investigating the incident, which happened at around 6.50pm on 5 May, on board Great Western Railway service between Chippenham and Bath Spa.
A man approached the teenager and started talking to him before he touched the boy inappropriately both above and below the waist.
A 28-year-old man from Portishead was arrested on suspicion of sexual assault. He has been released under police investigation whilst enquiries continue.
Another passenger on board this train challenged this man’s behaviour but to date this passenger has not spoken with police. It is believe he may have joined the service at Chippenham.
Officers are today appealing for that crucial witness to get in touch as soon as possible.
DC Denis Mahoney, said: “We will never tolerate unwanted sexual behaviour and we are working hard to investigate this incident.
“We are conscious another man travelling on this service witnessed what happened and spoke out. We are therefore appealing for them to get in touch as soon as possible. You may hold vital information which could help us investigate this sexual assault.”
Anyone with information should contact BTP by sending a text to 61016 or by calling 0800 40 50 40 quoting reference 563 of 05/05/2018.