A 19-year-old man is currently in a stable condition in hospital after being assaulted in Kettering yesterday (Wednesday) afternoon.
The man was assaulted just before 4pm in Tordoff Place.
During the incident, he had a number of items stolen including money and a mobile phone.
He was taken by air ambulance to University Hospital Coventry, where he is now receiving treatment.
Officers investigating the case have asked anyone who was in the Tordoff Place or School Lane area yesterday afternoon to contact them.
Witnesses, or anyone who knows anything about the incident can call Northamptonshire Police on 101 or they can call the independent charity Crimestoppers anonymously on 0800 555111 or use the anonymous online form at www.crimestoppers-uk.org.