Thames Valley Police is releasing an E-Fit image in connection with an attempted robbery which occurred in High Wycombe.
The incident took place on Tuesday, 13 February at about 5pm in an alleyway near the railway bridge, off Priory Avenue.
The victim, a 55-year-old man, was walking in the alleyway and approached the railway bridge, where he could see two men.
As he walked past them, he felt one of the man grab his rucksack and pull it in an attempt to steal it.
The victim then punched one of the offenders in an attempt to stop his backpack being stolen.
At this point one of the offenders assaulted him with a knife, causing a minor cut to his face.
The victim then fled the scene to seek assistance. He did not require hospital treatment and nothing was stolen during the incident.
The offender who assaulted the victim with a knife is an Asian man, aged in his early thirties, about 5ft 8ins tall and has a slim build.
He had a beard and spikey black hair, and was wearing a black tracksuit and black trainers.
Investigating officer, Detective Constable Dale Lester, of High Wycombe Local CID, said: “This incident could have left the victim with a more serious injury, and we would like to speak to the man in this E-Fit image.
“I would ask that anyone who recognises him or has any information which could help us locate him call us on 101.”
If you have any information relating to this case, please call 101 quoting reference '43180046774', or contact Crimestoppers anonymously.