Canal knifeman attacks girl, 17.
The 17-year-old was walking along the canal towpath near Dunns Bridge, on St Peters Road, in Dudley, when she was attacked. She escaped after her attacker was disturbed by a passer-by.
Acting Detective Inspector Andy Fennell said: "This was a very frightening ordeal for the young woman.
"We are hoping the member of public who disturbed the attack will come forward and furnish us with further details that may aid our investigation.
"Although a very serious incident we would like to make it clear we believe this is an isolated incident and crimes of this nature are rare within the locality."
The suspect is black, of a muscular build and around 6ft. He was wearing green camouflage trousers and a black woolly hat.
DI Fennell added: "The attacker spoke with a local accent and may frequent the local bus system - we are appealing to anyone that may recognise the description or have a name to speak to us."
Anyone with information on the assault, at about 11am on Saturday, December 8, is asked to call West Midlands Police on 101 or Crimestoppers, in confidence, on 0800 555 111.