Police want to speak to this man after a teenager was stabbed outside McDonald's in Piccadilly Gardens.
The incident happened at around 6.45pm on Monday, 28 December 2020.
The victim was stabbed behind the ear and suffered minor injuries.
He was taken to hospital but has since been released and has recovered, police said.
One man in his teens has so far been arrested and enquiries are ongoing.
Greater Manchester Police have now released an image of a person they would like to speak to.
He is described as in his late teens and of slim build, wearing a purple coloured Adidas hooded top and a black Adidas backpack.
Detective Constable Kassim of Greater Manchester Police said: "This incident took place at one of the busiest times of day in this area, and was no doubt distressing for any onlookers to witness."
"Thankfully the victim of this crime only suffered minor injuries and is now recovered. We'd like to speak to the man in this picture to continue our enquiries."
Anyone with any information about the assault should contact police on 0161 856 4409 quoting incident number 2197 of 2812020.
Information can be passed on anonymously by calling the independent charity Crimestoppers on 0800 555 111.
