A man was attacked at a park in Bolton.
Sometime between 8pm and 8.50pm on Friday 26 March 2010, the 21-year-old victim left Bolton town centre via Bradford Road.
He was walking through Great Lever Park when he was attacked by a group of six or seven youths.
During the attack, he was thrown to the ground and kicked and punched.
The victim also suffered a stab wound under his left arm.
A passer-by called an ambulance and the attackers fled.
The victim was taken to hospital, where among other injuries, he suffered a punctured lung.
He remains in hospital in a stable condition.
The attackers were all described as Asian youths who had been in the park in a group Detective Constable Richard Willoughby, based at Bolton CID, said: "The victim has been through a terrible ordeal and, albeit the stab wound turned out not to be too serious, it will take some time to move on from the attack.
"It is vital we find out exactly what happened and who is responsible - we are doing everything we can and if you know something that might help our investigation, please contact me.
"I would like to re-assure the community that police patrols have been stepped up in the area and will be providing a visible presence during the next few evenings."
Anyone with information is asked to call officers in Bolton on 0161 856 5740 or the independent charity Crimestoppers, anonymously, on 0800 555 111.