An attacker stabbed a passer-by in the stomach as he walked through the Racecourse in Northampton.
Sometime between 2.15am and 2.30am on Saturday, June 10, a man walking across the Racecourse was approached by a man and a woman.
The man became abusive, stabbed him once in the stomach before walking away in a different direction to the woman.
The victim made his way to Kingsley Park Terrace where he received treatment from an ambulance.
A spokeswoman for Northamptonshire Police said today: "The man is described as white, 5ft 5in, very slim, clean shaven and in his late teens or early 20s.
"He had short fair hair and was wearing a blue baseball cap. The woman was described as dual heritage, in her 20s, slim and around 5ft 10in.
"She had long black curly hair and was wearing a black jacket with a pink shirt underneath, and blue jeans."
Witnesses can contact police on 101 or Crimestoppers anonymously on 0800 555 111.