A man exposed himself to a woman while she was walking her dog across Kings Meadow in Great Cornard on Friday.
Police are appealing for witnesses after the incident which took place at around 1.30pm.
The 37-year-old woman was walking her dog and entered the meadow by the footpath that crosses the railway.
She became aware of man, who then followed her for a while, before disappearing. A police spokeswoman said: “She continued to walk along the footpath that ran alongside the river and then saw the man standing in front of her exposing himself. The victim continued walking.”
The offender is described as a black man, approximately 5ft 8ins tall, aged in his early to middle 20s. He was of medium build, had short dark hair and was wearing blue jeans and a black bomber-style jacket.