It is alleged a woman was targeted by a man as she walked home from the town centre, during the early hours of Saturday 18 July 2020.
The victim had been passing through Waterlow Road at around 12.30am when the incident took place.
The suspect is said to have followed the victim for a short distance, before carrying out the assault close to a car park for flats at Walsingham House.
He is described as being white, aged in his 20s, around 5ft 8ins tall and of slim build, with a dark goatee style beard and short cropped hair. He was wearing a dark coloured top and shorts.
Officers are continuing to carry out a number of enquiries, including forensic checks, identifying any possible CCTV opportunities and speaking to local residents.
Detective Constable Paul Wells, of the West Kent Vulnerability Investigation Team, said: ‘The suspect was first seen approaching the victim in Waterlow Road, from an area containing garages and a large skip bag for waste.
After the assault he then headed in the direction of Wheeler Street. He has a fairly distinctive description and we are urging anyone who may have seen him or who has any other information to call us.’
If you can help, contact the west Kent appeals line on 01622 604100, quoting reference 46/123021/20