A dog walker needed hospital treatment after an unprovoked assault in Oxford.
He was walking in a recreation ground off Oxford Road in Littlemore just after 11:00 BST on Sunday.
Police said the offender verbally abused the 52-year-old victim before "repeatedly punching" him in the face.
The dog walker, who was left with a broken nose and cuts to the face, was treated at the John Radcliffe Hospital in Oxford. Police are looking for a white man in his early 50s.
He had short brown hair and a tattoo half way down his right arm.
He was also walking a dog, believed to be a white bull terrier.