CCTV Police wish to speak to this man
The incident took place on the Manchester-bound X43 as the bus travelled along Manchester Road in Burnley on May 15.
A man touched the student as he sat next to her on the bus. He got off at the Craven Heifer pub bus stop in Rawtenstall.
DC Ian McLean from Burnley CID said: “I would appeal to anybody that recognises this man or with any information that could assist with our investigation to come forward and call me on 01282472142 or 101.”