A 70-year-old was taken to hospital after being assaulted in Dundee’s Camperdown Park.
The incident happened on Sunday at around 2.30pm while he was walking in the park with a woman.
He was attacked by another man who was walking a white Samoyed dog.
The pensioner suffered serious but non-life-threatening injuries and was taken to Ninewells.
Police say the suspect is described as white, aged 30-40, with short brown hair and stubble.
He wore a red puffer jacket, dark bottoms and white Nike Air Max shoes, with red and black flashes.
Detective Constable David Feeney, from Dundee CID, said: “There appears to have been no motive for this attack, which has left a man with a serious injury.
“I am asking for any members of the public who were in the park around the time of the incident, or who recognises the description of the suspect, to please come forward.
“Anyone with information can call police on 101, quoting incident 1739 of March 3.
“Alternatively, you can call Crimestoppers on 0800 555 111, if you wish to remain anonymous.”