Police said the incident was reported on Saturday when a boy was approached by a man and was allegedly sexually assaulted, police said.
The man was described as around 35 to 40 years old, about five foot nine, with a buzz cut and unshaven.
He was last seen wearing khaki shorts, sandals with multiple straps and dark sunglasses with a thin frame, police said. The man was not wearing a shirt, police added.
Anyone with information is asked to contact investigators.