A Luton woman out walking in the woods required stitches after being attacked by a stranger carrying a knife.
Detectives investigating the assault in Hitchin are appealing for witnesses and information.
The attack occurred in Oughtonhead Common on Saturday, June 4 at around 4.50pm.
Two women had been walking in the common when they walked past a man walking in the opposite direction.
The man assaulted one of the women with a knife causing a superficial wound.
The victim, aged in her 20s, required stitches as a result.
A 47-year-old man from Hitchin has been arrested on suspicion of assault and is currently in police custody.
However police are continuing to make enquiries and would urgently like to speak to anyone who was in the area at the time, or who has any information at all about the incident.
Investigating officer Detective Constable Kathryn Marshall, from the Hitchin Local Crime Unit, said: “First and foremost, I would like to reassure the public that this is a highly unusual incident in a quite area of Hitchin however the public are asked to remain vigilant.
“At the time of the incident there were lots of visitors to The Common and I would ask if you were there please contact me as soon as possible – in particular a female walking a black dog, a male and female with two children and a group of youths swimming in the river.”
Anyone with any information in relation to this incident is asked to contact Det Con Marshall or Hitchin Local Crime Unit via Hertfordshire Constabulary’s non-emergency number 101, quoting crime reference number G1/16/1372.
Alternatively, if you have any information about this incident you can contact the independent crime-fighting charity Crimestoppers anonymously on 0800 555 111.
No personal details are taken, information cannot be traced or recorded and you will never need to go to court.