A 40-year-old man described as "wearing a fisherman style hat" exposed himself to three teenage girls who were sitting in a community shelter in Northampton.
The incident happened on Thursday, April 13, between 10pm and 10.30pm on Billing Brook Road, Northamptonshire Police have today revealed.
He is described as a white, 5ft 6 inches tall, 40-year-old bald man with a large build and pale complexion.
A police spokeswoman said: "He was wearing a fisherman style hat with a peak, a blue bomber-style jacket, black cargo trousers and was carrying a drawstring bag."
Witnesses can contact police on 101 or Crimestoppers anonymously on 0800 111 555 using the incident number: 17000155644