A 38-year-old man is in a serious condition in hospital after being found lying in an alleyway in Northampton with head injuries.
The man was discovered in the alley between York Road and Abington Place at about 1.45pm on Sunday, May 5.
Police are appealing for two members of the public who came to his aid to come forward.
The man had sustained a serious head injury and was taken by ambulance to Northampton General Hospital. His condition has now worsened, and he has been transferred to the John Radcliffe Hospital in Oxford.
The first man who assisted the victim is in his 60s, white, 5ft 8in with a medium build and a beard. The second is black, in his early 30s, about 5ft 8in with a skinny build.