Police are appealing for witnesses after a man on a bike indecently exposed himself to two teenage girls and sexually assaulted one of them.
A spokesman for Sussex Police said the incident took place on a footpath between the town centre and Ifield.
Police said the man, who was on a grey/silver bicycle, accosted the girls while they were walking from The Dingle at 4.10pm on Saturday (June 14).
After they shouted at him to go away, he rode off in the direction of Tangmere Road.
The man was described as white, aged between 20 and 30, about 6ft tall, with blond hair.
He wore grey shorts, a dark blue top a black baseball cap with white at the front and spoke with an Eastern European accent.
Anyone with information was asked to phone Sussex Police on 101 or email firstname.lastname@example.org, quoting serial 1088 of 14/6.