North Yorkshire Police are appealing for witnesses to the incident in Thirsk to come forward.
They said it happened at around 3.20pm on Saturday (October 13) on a footpath between Sowerby Road and Topcliffe Road, leading to Holly Close.
A police spokesperson said: "The suspect is described as white, aged in his 30s, with medium length dark brown or black hair, slightly receding on the forehead, and a thick dark brown or black beard. He was wearing a dark clothing and white shoes."
Detective Constable Adam Scott added: “This is a very concerning incident, so I am asking anyone with information that could assist the investigation to contact the police.”
Witnesses should call North Yorkshire Police on 101.