Officers are appealing for witnesses to an attempted robbery on Church Way, Macclesfield.
The incident happened between 5pm and 5.15pm on Friday 10 November. Two men were walking on Church Way when they were approached by a men in a balaclava who threatened them both with a knife.
The offender demanded a bag from one of the victims and started going through the bag. When the victim pushed him away the offender stabbed him to his left leg.
The two victims fled the scene. Whilst they were running they became separated and the victim who had been stabbed asked for help from a member of the public near to the Co-op on Westmorland Close.
The second victim then came back for his friend and helped him to a place of safety.
Officers are appealing for any information about the incident – they are particularly keen to speak to the member of the public who was asked for help.
Detective Sergeant Angela Coppock said: “We would like to speak to the man who was asked for help and anyone else who might have seen what happened on the night.
“If you know anything please call Cheshire Police on 101, quoting incident number 842 of 10/11/2017.”
A 17-year-old boy has been arrested on suspicion of attempted robbery and released pending further inquiries.