Detectives in Shropshire are linking an attack on a woman in Oswestry with seven other similar incidents over the last 18 months.
A 32-year-old woman was grabbed and threatened with a kitchen knife as she crossed a disused railway line by the Sainsbury's supermarket at 0210 BST on Wednesday.
The attacker fled as a group of people approached.
Detective Constable David Harris, who is leading the investigation, said women should not walk home alone.
"The problem is, we do publicise these incidents in the press as and when they occur, but people have got the attitude 'it won't happen to me'.
"They think they'll be fine walking home on their own and it goes to show on a lot of occasions that isn't always the case."