At around 8am on Friday 6 November 2020 a 12-year-old boy was waiting to cross the road on Montgomery Avenue with his friend, near to the old swimming pool site.
A man and his terrier-type dog walked behind the victim and the dog barked at him, before biting the back of his leg. The boy sustained bruising.
The owner of the dog did not say anything to the victim and carried on walking past. He is described as a white man aged in his 60s.
Police Constable Jennie Sykes-Martin, of Dorset Police, said: “Following enquiries I have obtained an image of a man I would like to speak to.
“While I appreciate you are unable to see his face, I am hoping someone may recognise him from either the clothing he is wearing or the dog he is walking.
“I am keen to hear from anyone who may know the identity of the man.”
Anyone with information is asked to contact Dorset Police at www.dorset.police.uk, via email email@example.com or by calling 101, quoting occurrence number 55200167737.