A man and woman were involved in a fight with three men in Northampton town centre, which ended with one man being beaten unconscious.
The incident happened in Mercers Row between 6.30pm and 6.50pm on Saturday (April 8) and also saw a woman pushed to the floor.
One of the three men is described as black, about 5ft 5 inches, with an average build and in his early to mid-20s.
A spokeswoman for Northamptonshire Police: "He was wearing a black baseball cap, light coloured T-shirt and jeans and Airmax trainers. He was carrying a black shoulder bag.
"The second suspect is described as black, about 6ft 2 inches, skinny, in his late teens. He was wearing a black zipped hooded top, with the hood up, and a pale pink t-shirt.
"The third suspect was also black, about 5ft 11 inches, with an average muscular build and in his early to mid 20s. He was wearing a beige t-shirt."