Police are appealing for witnesses after a report of a suspicious man on the Whitton Recreation Ground in Shakespeare Road, Ipswich.
He is described as black, 40 years of age, tall and of medium build. He had dark hair which was shaved on one side and was wearing a blue jacket and dark shoes.
Armed police attended the scene and searched the area but were unable to find the suspect.
Enquiries on on-going.
Police are asking anyone with information to call police on 101.