A 21-year-old man was rushed to hospital after being stabbed and attacked by a gang of men wielding a machete, a screwdriver and a knife.
The victim was leaving the YMCA building in Central Milton Keynes when six men stopped him and asked if he had any drugs to sell.
When he told them he didn't, the men stabbed him so hard that his lung was punctured.
Thames Valley Police have only today released details of the attack, which happened on September 23 at 8pm.
They say the victim was taken to the John Radcliffe Hospital with a chest wound and a punctured lung. He has since been discharged.
The offenders were described as a group of six black and white males, all wearing dark clothing.
Investigating officer detective constable Kay O’Connor said: “We believe this was an isolated incident.
“It took place in a public area, where there could be potential witnesses and I would like to appeal to them.
"I would ask that anyone who witnessed this incident, or saw the victim following the incident, to come forward and speak to police."
Anyone with information should call police on 101, quoting reference 43190294889. They can also make reports online or call Crimestoppers anonymously on 0800 555 111.