A woman was sexually assaulted while travelling on a bus from Castleford.
The 21-year-old was making her way home to Wakefield on the 189 service when she was attacked on April 1.
Wakefield police are appealing for witnesses to the incident which took place at around 10pm.
A spokesman said: “The suspect is described as a white male aged around 19 years with a muscular build and short, light brown coloured hair.
“At the time of the incident he was thought to be wearing tight cream trousers a striped t-shirt and blue body warmer. He also had a tattoo on his right arm.”
Neighbourhood policing officers have increased patrols in the bus station areas to reassure people.
Any witnesses or anyone with information is asked to contact Det Con Katy Scarr on 01924 293873 or call Crimestoppers anonymously on 0800 555 111.