A woman was assaulted by a man outside a petrol station in Ossett on Saturday.
The attack took place at about 11.15am outside the BP garage, on Prospect Road.
An elderly couple interrupted the attack and asked the victim, who was on the floor with her attacker stood over her, if she was alright.
The elderly couple then walked off towards Towngate shops.
Anyone with information about the attack is asked to call 101 and ask for DC 3377 Ridley.