Sussex Police said a recent report of an indecent exposure in Preston Park could be linked to a number of similar incidents in the area last year.
Police said the latest report was received at 6.23pm on Monday, September 17, when a man approached a group of teenage girls and exposed himself to them.
One of the girls took a photograph of the man. Police have now released a picture of a man they want to speak to in connection with the incidents.
Sussex Police said from descriptions, it may be the same man who is suspected of a previous series of indecent exposures in the park in 2016/17. All have involved girls around their early teens.
Police have now increased patrols in the area, but are appealing for anyone with information on the suspect.
The man is described as white, in his mid-20s, and wearing a white top and green shorts. He was carrying a black Adidas bag. Previous reports suggest that he is around 6ft, of slim build and with short dark loosely curled hair.
Anyone who recognises the man is asked to report online or call 101 quoting serial 1019 of 17/09.