It follows an attack on a woman in her 30s who was jogging along the canal towpath at Bridge Lane/Hill Top at around 10.30am on Sunday.
West Yorkshire Police say a man approached her, sexually assaulted her and fled the scene when a woman walking her dog appeared.
The suspect is described as in his 30s, six feet tall, muscular, with broad shoulders, with tanned or olive-skinned and spoke with a foreign accent.
He had light brown hair with white highlights in it, and was wearing a long sleeved grey top and dark blue tracksuit bottoms.
It is thought that the woman who may have witnessed the assault is in her 50s and was walking a white and grey Jack Russell-type dog.
Sgt Phil Davis, of Wakefield CID, said: "We are continuing to appeal for information about this incident and I hope by the releasing the Efit that a member of the public will recognise the man and come forward with any information to assist with our enquiries.
"I would also ask for anyone who believes they know the woman walking her dog to contact police, as she may have information valuable to the investigation."
Anyone with information contact Wakefield CID on 101, quote crime reference 13170243260. Information can also be passed to independent charity Crimestoppers on 0800 555 111.