Police are hunting a man who committed a sex act while watching a woman walk her dog.
The 43-year-old woman was walking along a bank of the River Don near Leach Lane, Mexborough, when she saw a man exposing himself on the far bank.
The man - aged about 45, of medium build, 5ft 9ins tall, with short grey hair and wearing jeans and a T-shirt - was looking across the water towards her and carrying out a sexual act. He was disturbed by a passing cyclist, at about 9.20am on Monday.
Call police on 101.