Manhunt after female train passenger sexually assaulted
The incident happened between Dumbarton Central and Balloch in West Dunbartonshire.
Detectives are hunting a man who sexually assaulted a woman on a train.
British Transport Police said the incident happened between Dumbarton Central and Balloch, West Dunbartonshire, after the man blocked the aisle by standing between two seats.
As the woman tried to get past the man touched her inappropriately, causing her to stumble back, before he left the carriage.
Investigating officer constable Marc Higgins said: "This was an assault witnessed by another passenger on the train, who reported this to police.
"The victim herself, who asked other passengers if they'd seen what happened, has not reported the offence to us but that does not mean we'll stop investigating.
"We're committed to ensuring the railway is a safe place to travel for everyone and so if you were on the train and saw what happened, or if you are the woman who was assaulted in this manner, then please get in touch."
The man is white, in his early 30s, with short dark hair. He was wearing a black jacket, brown top and grey trousers.
The incident happened at around 8.25pm on September 23.
Anyone with information is asked to contact BTP on 0800 40 50 40 or text 61016 with reference 1700066980.