The incident happened around 16.30 BST on Friday, 15 April, in the public toilets at the east side of The Meadows near Hope Park Terrace.
A 14-year-old boy was approached by a man and sexually assaulted. A member of the public entered the toilets and the man left and walked off towards the crossroads at Hope Park Terrace.
The suspect is described as white, around 5ft 6ins, of slim build, with white stubble and aged around 70-years-old. He was wearing a dark jacket and trousers and a flat cap. He also used a walking stick.
Detective Inspector Grant Paterson said: “This attack has left the teenage boy exceptionally upset. We have officers on patrol in the area and if anyone has any concerns please speak to them or call us.
“This part of The Meadows would have been busy and I am asking anyone who saw this man or who may know who he is to get in touch.
“In particular, I am asking the member of the public who walked into the toilets as this was happening to get in touch. You may have information that is vital to our enquiries.”
Anyone who can help is asked to contact Police Scotland on 101, quoting incident number 2466 of Friday, 15 April. Or make a call anonymously to the charity Crimestoppers on 0800 555 111
