A man indecently exposed himself to a 13-year-old girl and a group of her friends in Northampton.
The incident happened in Redhill Park, Hunsbury, at 4.30pm on Wednesday June 25.
A spokesman for Northamptonshire Police said: “A 13-year-old girl and her friends had walked through the park towards a circular stone monument when the man walked up to them exposing himself.
“The teenagers ran away from the man, who was white, 5ft 8ins, of medium build, aged between 20 and 30.
“He was wearing a black baseball cap, wore white earphones, a black tee-shirt with white writing on it and black three-quarter length shorts which were baggy,” he added.
Witnesses or anyone who may recognise the description of the offender is asked to contact police on 101 or Crimestoppers anonymously on 0800 555 111.