A cyclist groped a teenage girl then rode off at speed a she shouted loudly after him.
The attack happened in Dyke Road around 10.30am on Tuesday, May 12, when the 17-year-old victim was walking past the Co-op on the west side of the street.
The man approached her, grabbed her buttock causing her pain and then rode off into Highdown Road.
As there were a lot of people in the area at the time, police are hoping that there may be a number of witnesses who have yet to come forward.
The man is described as white, aged 17-20, 5ft 6in-8in, of skinny build and wearing a burgundy hooded top with orange and white writing, baggy jeans and black trainers.
Anyone who witnessed the incident, saw the man riding off or who has any other information is asked to email 101@sussex.pnn.police.uk or call 101 quoting serial 469 of 12/05.