A man whose daughter was knocked over by a dog in a Northampton playing field was then head-butted by the offending owner.
The assault took place between 11.30am and midday on Monday, 3 April at Curtlee Hill, Wootton, Northampton.
A police spokeswoman said the victim was walking with his young daughter in the playing field there when she was knocked over by a dog. An "altercation" ensued with the dog’s owner who then head-butted the victim.
The offender is described as a white man in his mid-to-late 20s with a medium build, short, dark hair and facial stubble. He wore a white T-shirt, a dark zip-up top and grey bottoms. He also wore a gold chain and a black cap.
Witnesses, or anyone with information, are asked to contact Northamptonshire Police on 101. Alternatively, they can call independent charity Crimestoppers anonymously on 0800 555111.